Sometimes I get the following error while I was doing HttpWebRequest to a WebService. I copied my code below too.
System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it 127.0.0.1:80
at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.Sockets.Socket.InternalConnect(EndPoint remoteEP)
at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Int32 timeout, Exception& exception)
--- End of inner exception stack trace ---
at System.Net.HttpWebRequest.GetRequestStream()
ServicePointManager.CertificatePolicy = new TrustAllCertificatePolicy();
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.PreAuthenticate = true;
request.Credentials = networkCredential(sla);
request.Method = WebRequestMethods.Http.Post;
request.ContentType = "application/x-www-form-urlencoded";
request.Timeout = v_Timeout * 1000;
if (url.IndexOf("asmx") > 0 && parStartIndex > 0)
{
AppHelper.Logger.Append("#############" + sla.ServiceName);
using (StreamWriter reqWriter = new StreamWriter(request.GetRequestStream()))
{
while (true)
{
int index01 = parList.Length;
int index02 = parList.IndexOf("=");
if (parList.IndexOf("&") > 0)
index01 = parList.IndexOf("&");
string parName = parList.Substring(0, index02);
string parValue = parList.Substring(index02 + 1, index01 - index02 - 1);
reqWriter.Write("{0}={1}", HttpUtility.UrlEncode(parName), HttpUtility.UrlEncode(parValue));
if (index01 == parList.Length)
break;
reqWriter.Write("&");
parList = parList.Substring(index01 + 1);
}
}
}
else
{
request.ContentLength = 0;
}
response = (HttpWebResponse)request.GetResponse();
If this happens always, it literally means that the machine exists but that it has no services listening on the specified port, or there is a firewall stopping you.
If it happens occasionally - you used the word "sometimes" - and retrying succeeds, it is likely because the server has a full 'backlog'.
When you are waiting to be accepted on a listening socket, you are placed in a backlog. This backlog is finite and quite short - values of 1, 2 or 3 are not unusual - and so the OS might be unable to queue your request for the 'accept' to consume.
The backlog is a parameter on the listen function - all languages and platforms have basically the same API in this regard, even the C# one. This parameter is often configurable if you control the server, and is likely read from some settings file or the registry. Investigate how to configure your server.
If you wrote the server, you might have heavy processing in the accept of your socket, and this can be better moved to a separate worker-thread so your accept is always ready to receive connections. There are various architecture choices you can explore that mitigate queuing up clients and processing them sequentially.
Regardless of whether you can increase the server backlog, you do need retry logic in your client code to cope with this issue - as even with a long backlog the server might be receiving lots of other requests on that port at that time.
There is a rare possibility where a NAT router would give this error should its ports for mappings be exhausted. I think we can discard this possibility as too much of a long shot though, since the router has 64K simultaneous connections to the same destination address/port before exhaustion.
The most probable reason is a Firewall.
This article contains a set of reasons, which may be useful to you.
From the article, possible reasons could be:
FTP server settings
Software/Personal Firewall Settings
Multiple Software/Personal Firewalls
Anti-virus Software
LSP Layer
Router Firmware
Computer Turned Off
Computer Not Plugged In
Fiddler
I had the same. It was because the port-number of the web service was changing unexpectedly.
This problem usually happens when you have more than one copy of the project
My project was calling the Web service with a specific port number which I assigned in the Web.Config file of my main project file. As the port number changed unexpectedly, the browser was unable to find the Web service and throwing that error.
I solved this by following the below steps: (Visual Studio 2010)
Go to Properties of the Web service project --> click on Web tab --> In Servers section --> Check Specific port
and then assign the standard port number by which your main project is calling the web service.
I hope this will solve the problem.
Cheers :)
I think, you need to check your proxy settings in "internet options". If you are using proxy/'hide ip' applications, this problem may be occurs.
I had the same problem. The problem is that I didn't start the selenium server. I have downloaded the selenium server and i started it. After starting the selenium server, issue gone and all worked fine.
Refer this : http://coding-issues.blogspot.in/2012/11/no-connection-could-be-made-because.html
I had the same error with my WCF service using Net TCP binding, but resolved after starting the below services in my case.
Net.Pipe.Listener.Adapter
Net.TCP.Listener.Adapter
Net.Tcp Port Sharing Service
In my case, some domains worked, while some did not. Adding a reference to my organization's proxy Url in my web.config fixed the issue.
<system.net>
<defaultProxy useDefaultCredentials="true">
<proxy proxyaddress="http://proxy.my-org.com/" usesystemdefault="True"/>
</defaultProxy>
</system.net>
When you call service which has only HTTP (ex: http://example.com) and you call HTTPS (ex: https://example.com), you get exactly this error - "No connection could be made because the target machine actively refused it"
I faced same error because when your Server and Client run on same machine the Client need server local ip address not Public ip address to communicate with server you need Public ip address only in case when Server and Client run on separate machine so use Local ip address in client program to connect with server Local ip address can be found using this method.
public static string Getlocalip()
{
try
{
IPAddress[] localIPs = Dns.GetHostAddresses(Dns.GetHostName());
return localIPs[7].ToString();
}
catch (Exception)
{
return "null";
}
}
I got this error in an application that uses AppFabric. The clue was getting a DataCacheException in the stack trace. To see if this is the issue for you, run the following PowerShell command:
#("AppFabricCachingService","RemoteRegistry") | % { get-service $_ }
If either of these two services are stopped, then you will get this error.
For me, I wanted to start the mongo in shell (irrelevant of the exact context of the question, but having the same error message before even starting the mongo in shell)
The process 'MongoDB Service' wasn't running in Services
Start cmd as Administrator and type,
net start MongoDB
Just to see MongoDB is up and running just type mongo, in cmd it will give Mongo version details and Mongo Connection URL
Well, I've received this error today on Windows 8 64-bit out of the blue, for the first time, and it turns out my my.ini had been reset, and the bin/mysqld file had been deleted, among other items in the "Program Files/MySQL/MySQL Server 5.6" folder.
To fix it, I had to run the MySQL installer again, installing only the server, and copy a recent version of the my.ini file from "ProgramData/MySQL/MySQL Server 5.6", named my_2014-03-28T15-51-20.ini in my case (don't know how or why that got copied there so recently) back into "Program Files/MySQL/MySQL Server 5.6".
The only change to the system since MySQL worked was the installation of Native Instruments' Traktor 2 and a Traktor Audio 2 sound card, which really shouldn't have caused this problem, and no one else has used the system besides me. If anyone has a clue, it would be kind of you to comment to prevent this for me and anyone else who has encountered this.
For service reference within a solution.
Restart your workstation
Rebuild your solution
Update service reference in WCFclient project
At this point, I received messsage (Windows 7) to allow system access.
Then the service reference was updated properly without errors.
I would like to share this answer I found because the cause of the problem was not the firewall or the process not listening correctly, it was the code sample provided from Microsoft that I used.
https://msdn.microsoft.com/en-us/library/system.net.sockets.socket%28v=vs.110%29.aspx
I implemented this function almost exactly as written, but what happened is I got this error:
2016-01-05 12:00:48,075 [10] ERROR - The error is: System.Net.Sockets.SocketException (0x80004005): No connection could be made because the target machine actively refused it [fe80::caa:745:a1da:e6f1%11]:4080
This code would say the socket is connected, but not under the correct IP address actually needed for proper communication. (Provided by Microsoft)
private static Socket ConnectSocket(string server, int port)
{
Socket s = null;
IPHostEntry hostEntry = null;
// Get host related information.
hostEntry = Dns.GetHostEntry(server);
// Loop through the AddressList to obtain the supported AddressFamily. This is to avoid
// an exception that occurs when the host IP Address is not compatible with the address family
// (typical in the IPv6 case).
foreach(IPAddress address in hostEntry.AddressList)
{
IPEndPoint ipe = new IPEndPoint(address, port);
Socket tempSocket =
new Socket(ipe.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
tempSocket.Connect(ipe);
if(tempSocket.Connected)
{
s = tempSocket;
break;
}
else
{
continue;
}
}
return s;
}
I re-wrote the code to just use the first valid IP it finds. I am only concerned with IPV4 using this, but it works with localhost, 127.0.0.1, and the actually IP address of you network card, where the example provided by Microsoft failed!
private Socket ConnectSocket(string server, int port)
{
Socket s = null;
try
{
// Get host related information.
IPAddress[] ips;
ips = Dns.GetHostAddresses(server);
Socket tempSocket = null;
IPEndPoint ipe = null;
ipe = new IPEndPoint((IPAddress)ips.GetValue(0), port);
tempSocket = new Socket(ipe.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
Platform.Log(LogLevel.Info, "Attempting socket connection to " + ips.GetValue(0).ToString() + " on port " + port.ToString());
tempSocket.Connect(ipe);
if (tempSocket.Connected)
{
s = tempSocket;
s.SendTimeout = Coordinate.HL7SendTimeout;
s.ReceiveTimeout = Coordinate.HL7ReceiveTimeout;
}
else
{
return null;
}
return s;
}
catch (Exception e)
{
Platform.Log(LogLevel.Error, "Error creating socket connection to " + server + " on port " + port.ToString());
Platform.Log(LogLevel.Error, "The error is: " + e.ToString());
if (g_NoOutputForThreading == false)
rtbResponse.AppendText("Error creating socket connection to " + server + " on port " + port.ToString());
return null;
}
}
This is really specific, but if you receive this error after trying to connect to a database using mongo, what worked for me was running mongod.exe before running mongo.exe and then the connection worked fine. Hope this helps someone.
One more possibility --
Make sure you're trying to open the same IP address as where you're listening. My server app was listening to the host machine's IP address using IPv6, but the client was attempting to connect on the host machine's IPv4 address.
I've received this error from referencing services located on a WCFHost from my web tier. What worked for me may not apply to everyone, but I'm leaving this answer for those whom it may. The port number for my WCFHost was randomly updated by IIS, I simply had to update the end routes to the svc references in my web config. Problem solved.
In my scenario, I have two applications:
App1
App2
Assumption: App1 should listen to App2's activities on Port 5000
Error: Starting App1 and trying to listen, to a nonexistent ghost town, produces the error
Solution: Start App2 first, then try to listen using App1
Go to your WCF project -
properties ->
->
debuggers
-> unmark the checkbox
Enable Edit and Continue
In my case this was caused by a faulty deployment where a setting in my web.config was not made.
A collegue explained that the IP address in the error message represents the localhost.
When I corrected the web.config I was then using the correct url to make the server calls and it worked.
I thought I would post this in case it might help someone.
Using WampServer 64bit on Windows 7 Home Premium 64bit I encountered this exact problem. After hours and hours of experimentation it became apparent that all that was needed was in my.ini to comment out one line. Then it worked fine.
commented out 1 line
socket=mysql
If you put your old /data/ files in the appropriate location, WampServer will accept all of them except for the /mysql/ folder which it over writes. So then I simply imported a backup of the /mysql/ user data from my prior development environment and ran FLUSH PRIVILEGES in a phpMyAdmin SQL window. Works great. Something must be wrong because things shouldn't be this easy.
I had this issue happening often. I found SQL Server Agent service was not running. Once I started the service manually, it got fixed. Double check if the service is running or not:
Run prompt, type services.msc and hit enter
Find the service name - SQL Server Agent(Instance Name)
If SQL Server Agent is not running, double-click the service to open properties window. Then click on Start button. Hope it will help someone.
I came across this error and took some time to resolve it. In my case I had https and net.tcp configured as IIS bindings on same port. Obviously you can't have two things on the same port. I used netstat -ap tcp command to check whether there is something listening on that port. There was none listening. Removing unnecessary binding (https in my case) solved my issue.
It was a silly issue on my side, I had added a defaultproxy to my web.config in order to intercept traffic in Fiddler, and then forgot to remove it!
There is a service called "SQL Server Browser" that provides SQL Server connection information to clients.
In my case, none of the existing solutions worked because this service was not running. I resumed it and everything went back to working perfectly.
I was facing this issue today. Mine was Asp.Net Core API and it uses Postgresql as the database. We have configured this database as a Docker container. So the first step I did was to check whether I am able to access the database or not. To do that I searched for PgAdmin in the start as I have configured the same. Clicking on the resulted application will redirect you to the http://127.0.0.1:23722/browser/. There you can try access your database on the left menu. For me I was getting an error as in the below image.
Enter the password and try whether you are able to access it or not. For me it was not working. As it is a Docker container, I decided to restart my Docker desktop, to do that right click on the docker icon in the task bar and click restart.
Once after restarting the Docker, I was able to login and see the Database and also the error was gone when I restart the application in Visual Studio.
Hope it helps.
it might be because of authorisation issues; that was the case for me.
If you have for example: [Authorize("WriteAccess")] or [Authorize("ReadAccess")] at the top of your controller functions, try to comment them out.
I just faced this right now...
Here on my end, I have 2 separated Visual Studio solutions (.sln)... opened each one in their own Visual Studio instance.
Solution 2 calls Solution 1 code. The problem was related to the port assigned to Solution 1. I had to change the port on solution 1 to another one and then Solution 2 started working again. So make sure you check the port assigned to your project.
Normally, connection scripts do not mention the port to use. For example:
$mysqli = mysqli_connect('127.0.0.0.1', 'user', 'password', 'database');
So, to connect with a manager that doesn't use port 3306, you have to specify the port number on the connection request:
$mysqli = mysqli_connect('127.0.0.0.1', 'user', 'password', 'database', '3307');
To check the connections on the MySQL or MariaDB database manager, use the script:
wamp(64)\www\testmysql.php
by putting 'http://localhost/testmysql.php' in the browser address bar having first modified the script according to your parameters.
I forgot to start the service so it failed because no service was listening on port.
Resolved by starting the service.
Related
This question already has answers here:
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
(51 answers)
Closed 6 years ago.
I'm trying to connect to the local MySQL server but I keep getting an error.
Here is the code.
public class Connect {
public static void main(String[] args) {
Connection conn = null;
try {
String userName = "myUsername";
String password = "myPassword";
String url = "jdbc:mysql://localhost:3306/myDatabaseName";
Class.forName("com.mysql.jdbc.Driver").newInstance();
conn = DriverManager.getConnection(url, userName, password);
System.out.println("Database connection established");
} catch (Exception e) {
System.err.println("Cannot connect to database server");
System.err.println(e.getMessage());
e.printStackTrace();
} finally {
if (conn != null) {
try {
conn.close();
System.out.println("Database Connection Terminated");
} catch (Exception e) {}
}
}
}
}
and the errors :
Cannot connect to database server
Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1116)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:344)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2333)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2370)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2154)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:792)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:381)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at Connect.main(Connect.java:16)
Caused by: java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:529)
at java.net.Socket.connect(Socket.java:478)
at java.net.Socket.<init>(Socket.java:375)
at java.net.Socket.<init>(Socket.java:218)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:257)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:294)
... 15 more
I've set the classpath, made sure my.cnf had the skip network option commented out.
java version is 1.2.0_26 (64 bit)
mysql 5.5.14
mysql connector 5.1.17
I made sure that the user had access to my database.
I have had the same problem in two of my programs. My error was this:
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
I spent several days to solve this problem. I have tested many approaches that have been mentioned in different web sites, but non of them worked. Finally I changed my code and found out what was the problem. I'll try to tell you about different approaches and sum them up here.
While I was seeking the internet to find the solution for this error, I figured out that there are many solutions that worked for at least one person, but others say that it doesn't work for them! why there are many approaches to this error?
It seems this error can occur generally when there is a problem in connecting to the server. Maybe the problem is because of the wrong query string or too many connections to the database.
So I suggest you to try all the solutions one by one and don't give up!
Here are the solutions that I found on the internet and for each of them, there is at least on person who his problem has been solved with that solution.
Tip: For the solutions that you need to change the MySQL settings, you can refer to the following files:
Linux: /etc/mysql/my.cnf or /etc/my.cnf (depending on the Linux distribution and MySQL package used)
Windows: C:\**ProgramData**\MySQL\MySQL Server 5.6\my.ini (Notice it's ProgramData, not Program Files)
Here are the solutions:
changing bind-address attribute:
Uncomment bind-address attribute or change it to one of the following IPs:
bind-address="127.0.0.1"
or
bind-address="0.0.0.0"
commenting out "skip-networking"
If there is a skip-networking line in your MySQL config file, make it comment by adding # sign at the beginning of that line.
change "wait_timeout" and "interactive_timeout"
Add these lines to the MySQL config file:
[wait_timeout][1] = *number*
interactive_timeout = *number*
connect_timeout = *number*
Make sure Java isn't translating 'localhost' to [:::1] instead of [127.0.0.1]
Since MySQL recognizes 127.0.0.1 (IPv4) but not :::1 (IPv6)
This could be avoided by using one of two approaches:
In the connection string use 127.0.0.1 instead of localhost to avoid localhost being translated to :::1
Run java with the option -Djava.net.preferIPv4Stack=true to force java to use IPv4 instead of IPv6. On Linux, this could also be achieved by running (or placing it inside /etc/profile:
export _JAVA_OPTIONS="-Djava.net.preferIPv4Stack=true"
check Operating System proxy settings, firewalls and anti-virus programs
Make sure the Firewall, or Anti-virus software isn't blocking MySQL service.
Stop iptables temporarily on linux. If iptables are misconfigured they may allow tcp packets to be sent to mysql port, but block tcp packets from coming back on the same connection.
# Redhat enterprise and CentOS
systemctl stop iptables.service
# Other linux distros
service iptables stop
Stop anti-virus software on Windows.
change connection string
Check your query string. your connection string should be some thing like this:
dbName = "my_database";
dbUserName = "root";
dbPassword = "";
String connectionString = "jdbc:mysql://localhost/" + dbName + "?user=" + dbUserName + "&password=" + dbPassword + "&useUnicode=true&characterEncoding=UTF-8";
Make sure you don't have spaces in your string. All the connection string should be continues without any space characters.
Try to replace "localhost" with the loopback address 127.0.0.1.
Also try to add port number to your connection string, like:
String connectionString = "jdbc:mysql://localhost:3306/my_database?user=root&password=Pass&useUnicode=true&characterEncoding=UTF-8";
Usually default port for MySQL is 3306.
Don't forget to change username and password to the username and password of your MySQL server.
update your JDK driver library file
test different JDK and JREs (like JDK 6 and 7)
don't change max_allowed_packet
"max_allowed_packet" is a variable in MySQL config file that indicates the maximum packet size, not the maximum number of packets. So it will not help to solve this error.
change tomcat security
change TOMCAT6_SECURITY=yes to TOMCAT6_SECURITY=no
use validationQuery property
use validationQuery="select now()" to make sure each query has responses
AutoReconnect
Add this code to your connection string:
&autoReconnect=true&failOverReadOnly=false&maxReconnects=10
Although non of these solutions worked for me, I suggest you to try them. Because there are some people who solved their problem with following these steps.
But what solved my problem?
My problem was that I had many SELECTs on database. Each time I was creating a connection and then closing it. Although I was closing the connection every time, but the system faced with many connections and gave me that error. What I did was that I defined my connection variable as a public (or private) variable for whole class and initialized it in the constructor. Then every time I just used that connection. It solved my problem and also increased my speed dramatically.
#Conclusion#
There is no simple and unique way to solve this problem. I suggest you to think about your own situation and choose above solutions. If you take this error at the beginning of the program and you are not able to connect to the database at all, you might have problem in your connection string. But If you take this error after several successful interaction to the database, the problem might be with number of connections and you may think about changing "wait_timeout" and other MySQL settings or rewrite your code how that reduce number of connections.
If you are using MAMP PRO, the easy fix, which I really wish I had realized before I started searching the internet for days trying to figure this out. Its really this simple...
You just have to click "Allow Network Access to MySQL" from the MAMP MySQL tab.
Really, thats it.
Oh, and you MIGHT have to still change your bind address to either 0.0.0.0 or 127.0.0.1 like outlined in the posts above, but clicking that box alone will probably solve your problems if you are a MAMP user.
Setting the bind-address to the server's network IP instead of the localhost default, and setting privileges on my user worked for me.
my.cnf:
bind-address = 192.168.123.456
MySql Console:
GRANT ALL PRIVILEGES ON dbname.* to username#'%' IDENTIFIED BY 'password';
In my case,
Change the remote machine mysql configuration at /etc/mysql/my.cnf: change
bind-address = 127.0.0.1
to
#bind-address = 127.0.0.1
On the remote machine, change mysql user permissions with
GRANT ALL PRIVILEGES ON *.* TO 'user'#'%' IDENTIFIED BY 'password';
IMPORTANT: restart mysql on the remote machine: sudo /etc/init.d/mysql restart
I've just faced the same problem.
It happened because the MySQL Daemon was binded to the IP of the machine, which is required to make connection with an user that has permission to connect #your_machine.
In this case, the user should have permission to connect USER_NAME#MACHINE_NAME_OR_IP
I wanted remote access to my machine so I changed in my.cnf from
bind-address = MY_IP_ADDRESS
To
bind-address = 0.0.0.0
Which will allow an user from localhost AND even outside (in my case) to connect to the instance.
Both below permissions will work if you bind the MySQL to 0.0.0.0:
USER_NAME#MACHINE_NAME_OR_IP
USER_NAME#localhost
In my case (I am a noob), I was testing Servlet that make database connection with MySQL and one of the Exception is the one mentioned above.
It made my head swing for some seconds but I came to realize that it was because I have not started my MySQL server in localhost.
After starting the server, the problem was fixed.
So, check whether MySQL server is running properly.
In case you are having problem with a set of Docker containers, then make sure that you do not only EXPOSE the port 3306, but as well map the port from outside the container -p 3306:3306. For docker-compose.yml:
version: '2'
services:
mdb:
image: mariadb:10.1
ports:
- "3306:3306"
…
In my case it was an idle timeout, that caused the connection to be dropped on the server. The connection was kept open, but not used for a long period of time. Then a client restart works, while I believe a reconnect will work as well.
A not bad solution is to have a daemon/service to ping the connection from time to time.
As the detailed answer above says, this error can be caused by many things.
I had this problem too. My setup was Mac OSX 10.8, using a Vagrant managed VirtualBox VM of Ubuntu 12.04, with MySQL 5.5.34.
I had correctly setup port forwarding in the Vagrant config file. I could telnet to the MySQL instance both from my Mac and from within the VM. So I knew the MySQL daemon was running and reachable. But when I tried to connect over JDBC, I got the "Communications link failure" error.
In my case, the problem was solved by editing the /etc/mysql/my.cnf file. Specifically, I commented out the "#bind-address=127.0.0.1" line.
The resolution provided by Soheil was successful in my case.
To clarify, the only change I needed to make was with MySQL's server configuration;
bind-address = **INSERT-IP-HERE**
I am using an external MySQL server for my application. It is a basic Debian 7.5 installation with MySQL Server 5.5 - default configuration.
IMPORTANT:
Always backup the original of any configuration files you may modify. Always take care when elevated as super user.
File
/etc/mysql/my.cnf
Line
bind-address = 192.168.0.103 #127.0.0.1
Restart your MySQL Server service:
/usr/sbin/service mysql restart
As you can see, I simply provided the network IP of the server and commented out the default entry. Please note that simply copy and paste my solution will not work for you, unless by some miracle our hosts share the same IP.
Thanks # Soheil
I know this is an old thread but I have tried numerous things and fixed my issue using the following means..
I'm developing a cross platform app on Windows but to be used on Linux and Windows servers.
A MySQL database called "jtm" installed on both systems. For some reason, in my code I had the database name as "JTM". On Windows it worked fine, in fact on several Windows systems it flew along.
On Ubuntu I got the error above time and time again. I tested it out with the correct case in the code "jtm" and it works a treat.
Linux is obviously a lot less forgiving about case sensitivity (rightly so), whereas Windows makes allowances.
I feel a bit daft now but check everything. The error message is not the best but it does seem fixable if you persevere and get things right.
I just restarted MySQL (following a tip from here: https://stackoverflow.com/a/14238800) and it solved the issue.
I had the same issue on MacOS (10.10.2) and MySql (5.6.21) installed via homebrew.
The confusing thing was that one of my apps connected to the database fine and the other was not.
After trying many things on the app that threw the exception com.mysql.jdbc.CommunicationsException as suggested by the accepted answer of this question to no avail, I was surprised that restarting MySQL worked.
The cause of my issue might have been the following as suggested in the answer in the aforementioned link:
Are you using connection pool ? If yes, then try to restart the
server. Probably few of the connections in your connection pool are in closed state.
It happens (in my case) when there is not enough memory for MySQL. A restart fixes it, but if that's the case consider a nachine with more memory, or limit the memory taken by jvms
Go to Windows services in the control panel and start the MySQL service. For me it worked. When I was doing a Java EE project I got this error" Communication link failure". I restarted my system and then it worked.
After that I again got the same error even after restarting my system. Then I tried to open the MySQL command line console and login with root, even then it gave me an error.
Finally when I started the MySQL service from Windows services, it worked.
Had the same.
Removing port helped in my case, so I left it as jdbc:mysql://localhost/
For me the solution was to change in the conf file of mysql server the parameter bind-address="127.0.0.1" or bind-address="x.x.x.x" to bind-address="0.0.0.0".
Thanks.
If you are using hibernate, this error can be caused for keeping open a Session object more time than wait_timeout
I've documented a case in here for those who are interested.
I found the solution
since MySQL need the Localhost in-order to work.
go to /etc/network/interfaces file and make sure you have the localhost configuration set there:
auto lo
iface lo inet loopback
NOW RESTART the Networking subsystem and the MySQL Services:
sudo /etc/init.d/networking restart
sudo /etc/init.d/mysql restart
Try it now
It is majorly because of weak connection between mysql client and remote mysql server.
In my case it is because of flaky VPN connection.
In phpstorm + vagrant autoReconnect driver option helped.
I was experiencing similar problem and the solution for my case was
changing bind-address = 0.0.0.0 from 127.0.0.1
changing url's localhost to localhost:3306
the thing i felt is we should never give up, i tried every options from this post and from other forums as well...happy it works #saurab
I faced this problem also.
As Soheil suggested,
I went to php.ini file at the path C:\windows\php.ini , then I revised port number in this file.
it is on the line mysqli.default_port =..........
So I changed it in my java app as it's in the php.ini file,now it works fine with me.
For Windows :-
Goto start menu write , "MySqlserver Instance Configuration Wizard" and reconfigure your mysql server instance.
Hope it will solve your problem.
After years having the same issue and no permanent solution this is whats solved it for the past 3 weeks (which is a record in terms of error free operation)
set global wait_timeout=3600;
set global interactive_timeout=230400;
Don't forget to make this permanent if it works for you.
If you are using local emulator, you have to use IP address 10.0.2.2 instead of localhost to access to your local MySQL server.
This question already has answers here:
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
(51 answers)
Closed 6 years ago.
I'm trying to connect to the local MySQL server but I keep getting an error.
Here is the code.
public class Connect {
public static void main(String[] args) {
Connection conn = null;
try {
String userName = "myUsername";
String password = "myPassword";
String url = "jdbc:mysql://localhost:3306/myDatabaseName";
Class.forName("com.mysql.jdbc.Driver").newInstance();
conn = DriverManager.getConnection(url, userName, password);
System.out.println("Database connection established");
} catch (Exception e) {
System.err.println("Cannot connect to database server");
System.err.println(e.getMessage());
e.printStackTrace();
} finally {
if (conn != null) {
try {
conn.close();
System.out.println("Database Connection Terminated");
} catch (Exception e) {}
}
}
}
}
and the errors :
Cannot connect to database server
Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1116)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:344)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2333)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2370)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2154)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:792)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:381)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at Connect.main(Connect.java:16)
Caused by: java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:529)
at java.net.Socket.connect(Socket.java:478)
at java.net.Socket.<init>(Socket.java:375)
at java.net.Socket.<init>(Socket.java:218)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:257)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:294)
... 15 more
I've set the classpath, made sure my.cnf had the skip network option commented out.
java version is 1.2.0_26 (64 bit)
mysql 5.5.14
mysql connector 5.1.17
I made sure that the user had access to my database.
I have had the same problem in two of my programs. My error was this:
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
I spent several days to solve this problem. I have tested many approaches that have been mentioned in different web sites, but non of them worked. Finally I changed my code and found out what was the problem. I'll try to tell you about different approaches and sum them up here.
While I was seeking the internet to find the solution for this error, I figured out that there are many solutions that worked for at least one person, but others say that it doesn't work for them! why there are many approaches to this error?
It seems this error can occur generally when there is a problem in connecting to the server. Maybe the problem is because of the wrong query string or too many connections to the database.
So I suggest you to try all the solutions one by one and don't give up!
Here are the solutions that I found on the internet and for each of them, there is at least on person who his problem has been solved with that solution.
Tip: For the solutions that you need to change the MySQL settings, you can refer to the following files:
Linux: /etc/mysql/my.cnf or /etc/my.cnf (depending on the Linux distribution and MySQL package used)
Windows: C:\**ProgramData**\MySQL\MySQL Server 5.6\my.ini (Notice it's ProgramData, not Program Files)
Here are the solutions:
changing bind-address attribute:
Uncomment bind-address attribute or change it to one of the following IPs:
bind-address="127.0.0.1"
or
bind-address="0.0.0.0"
commenting out "skip-networking"
If there is a skip-networking line in your MySQL config file, make it comment by adding # sign at the beginning of that line.
change "wait_timeout" and "interactive_timeout"
Add these lines to the MySQL config file:
[wait_timeout][1] = *number*
interactive_timeout = *number*
connect_timeout = *number*
Make sure Java isn't translating 'localhost' to [:::1] instead of [127.0.0.1]
Since MySQL recognizes 127.0.0.1 (IPv4) but not :::1 (IPv6)
This could be avoided by using one of two approaches:
In the connection string use 127.0.0.1 instead of localhost to avoid localhost being translated to :::1
Run java with the option -Djava.net.preferIPv4Stack=true to force java to use IPv4 instead of IPv6. On Linux, this could also be achieved by running (or placing it inside /etc/profile:
export _JAVA_OPTIONS="-Djava.net.preferIPv4Stack=true"
check Operating System proxy settings, firewalls and anti-virus programs
Make sure the Firewall, or Anti-virus software isn't blocking MySQL service.
Stop iptables temporarily on linux. If iptables are misconfigured they may allow tcp packets to be sent to mysql port, but block tcp packets from coming back on the same connection.
# Redhat enterprise and CentOS
systemctl stop iptables.service
# Other linux distros
service iptables stop
Stop anti-virus software on Windows.
change connection string
Check your query string. your connection string should be some thing like this:
dbName = "my_database";
dbUserName = "root";
dbPassword = "";
String connectionString = "jdbc:mysql://localhost/" + dbName + "?user=" + dbUserName + "&password=" + dbPassword + "&useUnicode=true&characterEncoding=UTF-8";
Make sure you don't have spaces in your string. All the connection string should be continues without any space characters.
Try to replace "localhost" with the loopback address 127.0.0.1.
Also try to add port number to your connection string, like:
String connectionString = "jdbc:mysql://localhost:3306/my_database?user=root&password=Pass&useUnicode=true&characterEncoding=UTF-8";
Usually default port for MySQL is 3306.
Don't forget to change username and password to the username and password of your MySQL server.
update your JDK driver library file
test different JDK and JREs (like JDK 6 and 7)
don't change max_allowed_packet
"max_allowed_packet" is a variable in MySQL config file that indicates the maximum packet size, not the maximum number of packets. So it will not help to solve this error.
change tomcat security
change TOMCAT6_SECURITY=yes to TOMCAT6_SECURITY=no
use validationQuery property
use validationQuery="select now()" to make sure each query has responses
AutoReconnect
Add this code to your connection string:
&autoReconnect=true&failOverReadOnly=false&maxReconnects=10
Although non of these solutions worked for me, I suggest you to try them. Because there are some people who solved their problem with following these steps.
But what solved my problem?
My problem was that I had many SELECTs on database. Each time I was creating a connection and then closing it. Although I was closing the connection every time, but the system faced with many connections and gave me that error. What I did was that I defined my connection variable as a public (or private) variable for whole class and initialized it in the constructor. Then every time I just used that connection. It solved my problem and also increased my speed dramatically.
#Conclusion#
There is no simple and unique way to solve this problem. I suggest you to think about your own situation and choose above solutions. If you take this error at the beginning of the program and you are not able to connect to the database at all, you might have problem in your connection string. But If you take this error after several successful interaction to the database, the problem might be with number of connections and you may think about changing "wait_timeout" and other MySQL settings or rewrite your code how that reduce number of connections.
If you are using MAMP PRO, the easy fix, which I really wish I had realized before I started searching the internet for days trying to figure this out. Its really this simple...
You just have to click "Allow Network Access to MySQL" from the MAMP MySQL tab.
Really, thats it.
Oh, and you MIGHT have to still change your bind address to either 0.0.0.0 or 127.0.0.1 like outlined in the posts above, but clicking that box alone will probably solve your problems if you are a MAMP user.
Setting the bind-address to the server's network IP instead of the localhost default, and setting privileges on my user worked for me.
my.cnf:
bind-address = 192.168.123.456
MySql Console:
GRANT ALL PRIVILEGES ON dbname.* to username#'%' IDENTIFIED BY 'password';
In my case,
Change the remote machine mysql configuration at /etc/mysql/my.cnf: change
bind-address = 127.0.0.1
to
#bind-address = 127.0.0.1
On the remote machine, change mysql user permissions with
GRANT ALL PRIVILEGES ON *.* TO 'user'#'%' IDENTIFIED BY 'password';
IMPORTANT: restart mysql on the remote machine: sudo /etc/init.d/mysql restart
I've just faced the same problem.
It happened because the MySQL Daemon was binded to the IP of the machine, which is required to make connection with an user that has permission to connect #your_machine.
In this case, the user should have permission to connect USER_NAME#MACHINE_NAME_OR_IP
I wanted remote access to my machine so I changed in my.cnf from
bind-address = MY_IP_ADDRESS
To
bind-address = 0.0.0.0
Which will allow an user from localhost AND even outside (in my case) to connect to the instance.
Both below permissions will work if you bind the MySQL to 0.0.0.0:
USER_NAME#MACHINE_NAME_OR_IP
USER_NAME#localhost
In my case (I am a noob), I was testing Servlet that make database connection with MySQL and one of the Exception is the one mentioned above.
It made my head swing for some seconds but I came to realize that it was because I have not started my MySQL server in localhost.
After starting the server, the problem was fixed.
So, check whether MySQL server is running properly.
In case you are having problem with a set of Docker containers, then make sure that you do not only EXPOSE the port 3306, but as well map the port from outside the container -p 3306:3306. For docker-compose.yml:
version: '2'
services:
mdb:
image: mariadb:10.1
ports:
- "3306:3306"
…
In my case it was an idle timeout, that caused the connection to be dropped on the server. The connection was kept open, but not used for a long period of time. Then a client restart works, while I believe a reconnect will work as well.
A not bad solution is to have a daemon/service to ping the connection from time to time.
As the detailed answer above says, this error can be caused by many things.
I had this problem too. My setup was Mac OSX 10.8, using a Vagrant managed VirtualBox VM of Ubuntu 12.04, with MySQL 5.5.34.
I had correctly setup port forwarding in the Vagrant config file. I could telnet to the MySQL instance both from my Mac and from within the VM. So I knew the MySQL daemon was running and reachable. But when I tried to connect over JDBC, I got the "Communications link failure" error.
In my case, the problem was solved by editing the /etc/mysql/my.cnf file. Specifically, I commented out the "#bind-address=127.0.0.1" line.
The resolution provided by Soheil was successful in my case.
To clarify, the only change I needed to make was with MySQL's server configuration;
bind-address = **INSERT-IP-HERE**
I am using an external MySQL server for my application. It is a basic Debian 7.5 installation with MySQL Server 5.5 - default configuration.
IMPORTANT:
Always backup the original of any configuration files you may modify. Always take care when elevated as super user.
File
/etc/mysql/my.cnf
Line
bind-address = 192.168.0.103 #127.0.0.1
Restart your MySQL Server service:
/usr/sbin/service mysql restart
As you can see, I simply provided the network IP of the server and commented out the default entry. Please note that simply copy and paste my solution will not work for you, unless by some miracle our hosts share the same IP.
Thanks # Soheil
I know this is an old thread but I have tried numerous things and fixed my issue using the following means..
I'm developing a cross platform app on Windows but to be used on Linux and Windows servers.
A MySQL database called "jtm" installed on both systems. For some reason, in my code I had the database name as "JTM". On Windows it worked fine, in fact on several Windows systems it flew along.
On Ubuntu I got the error above time and time again. I tested it out with the correct case in the code "jtm" and it works a treat.
Linux is obviously a lot less forgiving about case sensitivity (rightly so), whereas Windows makes allowances.
I feel a bit daft now but check everything. The error message is not the best but it does seem fixable if you persevere and get things right.
I just restarted MySQL (following a tip from here: https://stackoverflow.com/a/14238800) and it solved the issue.
I had the same issue on MacOS (10.10.2) and MySql (5.6.21) installed via homebrew.
The confusing thing was that one of my apps connected to the database fine and the other was not.
After trying many things on the app that threw the exception com.mysql.jdbc.CommunicationsException as suggested by the accepted answer of this question to no avail, I was surprised that restarting MySQL worked.
The cause of my issue might have been the following as suggested in the answer in the aforementioned link:
Are you using connection pool ? If yes, then try to restart the
server. Probably few of the connections in your connection pool are in closed state.
It happens (in my case) when there is not enough memory for MySQL. A restart fixes it, but if that's the case consider a nachine with more memory, or limit the memory taken by jvms
Go to Windows services in the control panel and start the MySQL service. For me it worked. When I was doing a Java EE project I got this error" Communication link failure". I restarted my system and then it worked.
After that I again got the same error even after restarting my system. Then I tried to open the MySQL command line console and login with root, even then it gave me an error.
Finally when I started the MySQL service from Windows services, it worked.
Had the same.
Removing port helped in my case, so I left it as jdbc:mysql://localhost/
For me the solution was to change in the conf file of mysql server the parameter bind-address="127.0.0.1" or bind-address="x.x.x.x" to bind-address="0.0.0.0".
Thanks.
If you are using hibernate, this error can be caused for keeping open a Session object more time than wait_timeout
I've documented a case in here for those who are interested.
I found the solution
since MySQL need the Localhost in-order to work.
go to /etc/network/interfaces file and make sure you have the localhost configuration set there:
auto lo
iface lo inet loopback
NOW RESTART the Networking subsystem and the MySQL Services:
sudo /etc/init.d/networking restart
sudo /etc/init.d/mysql restart
Try it now
It is majorly because of weak connection between mysql client and remote mysql server.
In my case it is because of flaky VPN connection.
In phpstorm + vagrant autoReconnect driver option helped.
I was experiencing similar problem and the solution for my case was
changing bind-address = 0.0.0.0 from 127.0.0.1
changing url's localhost to localhost:3306
the thing i felt is we should never give up, i tried every options from this post and from other forums as well...happy it works #saurab
I faced this problem also.
As Soheil suggested,
I went to php.ini file at the path C:\windows\php.ini , then I revised port number in this file.
it is on the line mysqli.default_port =..........
So I changed it in my java app as it's in the php.ini file,now it works fine with me.
For Windows :-
Goto start menu write , "MySqlserver Instance Configuration Wizard" and reconfigure your mysql server instance.
Hope it will solve your problem.
After years having the same issue and no permanent solution this is whats solved it for the past 3 weeks (which is a record in terms of error free operation)
set global wait_timeout=3600;
set global interactive_timeout=230400;
Don't forget to make this permanent if it works for you.
If you are using local emulator, you have to use IP address 10.0.2.2 instead of localhost to access to your local MySQL server.
I'm in a situation where I have to push data to a remote database, from a Powershell script.
The database's server uses multiple instances, each one using a specific socket.
I'm trying to open a connection remotely, using the .Net MySQL connector as follow :
$mdir = Split-Path $script:MyInvocation.MyCommand.Path
[void][system.reflection.Assembly]::LoadFrom("$mdir\MySQL.Data.dll")
$connection = New-Object MySql.Data.MySqlClient.MySqlConnection
$connection.ConnectionString = "host=$myHost;port=$Port;uid=$User;pwd=$Pass;database=$Database;Socket=$Socket;Pooling=False"
$connection.Open()
I'm getting an error saying that Socket is not an existing keyword.
I've found reference to that keyword on google, but indeed not in the official documentation.
Example showing what I want to connect to :
Server : db.domain.com
Port : 2345
Socket : /var/sockets/mycustomsocket.sock
Is there a way to do what I want, and if so, what am I doing wrong ?
EDIT
What I was doing wrong is putting too much trust into the technical knowledge of my client, but at least, I learned something !
The case I described is pure nonsense due to the way MySQL works.
When an instance uses a socket, that socket is bound to a specific port. The case that my client described to me that lead to that question is therefore impossible.
It is not possible to have several instances of MySQL listening on the same port, but using different sockets. Wanting to connect to a remote file socket is therefore a non issue, and you should be able to connect using ip/hostname and port.
The Socket parameter in MySQL is supposed to be used locally, as it was noted in the comments.
I downloaded and installed the driver setup file, DB2OLEDB.exe, from here:
http://download.microsoft.com/mwg-internal/de5fs23hu73ds/progress?id=HYLbKUfGNl
Using the connection string that worked on another PC, I tried to create a Connection Object in an SSIS package. When I tested the connection I got this error:
Test connection failed because of an error in initializing provider. A TCPIP socket error has occurred (10057): A request to send or receive data was disallowed because the socket is not connected and (when sending on a datagram socket using a sendto call) no address was supplied.
Any suggestions on what the cause of this error is and how I might resolve this issue?
By the way, when I use the DB2 Configuration set up utility and test a connection from within that, I am able to successfully connect.
What other info can I provide to help you answer this question?
Thank you
Could this be related to a blocked port?
If you follow all the steps illustrated here: http://www.bidn.com/blogs/PatrickLeBlanc/ssis/700/connecting-to-db2-using-ssis do you still get the same result?
Maybe a silly question, did you restart the computer after the installation?
Are you an admin user on one machine and not on the other?
You could try to verify the port connectivity with a quick telnet command:
telnet your-db-host your-db-listening-port
If it connects, that one is off the list.
Doing some research I've found two possible fixes.
The first link suggests calling BeginReceive after the EndAccept logic is complete. Are you using script code, or just using the GUI without any scripting?
TCP async sockets throwing 10057
The second link points to drivers / software on the PC. It could be that you are missing a windows update or have faulty hardware / drivers.
I think this is less likely the case since you could connect to a different machine with the same connection string(?). Can you verify this is a valid statement?
http://social.msdn.microsoft.com/Forums/en-US/1bc3df95-c86d-4d25-aa20-30f61ed00c63/odd-socket-errors
If you could show the connection strings used for both the working and non working, and give a little more detail about The "Other PC" in comparison to the non-working PC... that would be helpful =]
If neither of the posts I've linked are the solution, this specific Google search has proven to yield some seemingly helpful results
"socket" "10057" "no address was supplied."
I've got a trio of Windows servers (data1, data2 and datawitness) that aren't part of any domain and don't use AD. I'm trying to set up mirroring based on the instructions at http://alan328.com/SQL2005_Database_Mirroring_Tutorial.aspx. I've had success right up until the final set of instructions where I tell data1 to use datawitness as the witness server. That step fails with the following message:
alter database MyDatabase set witness = 'TCP://datawitness.somedomain.com:7024'
The ALTER DATABASE command could not be sent to the remote server instance 'TCP://datawitness.somedomain.com:7024'. The database mirroring configuration was not changed. Verify that the server is connected, and try again.
I've tested both port 7024 as well as 1433 using telnet and both servers can indeed connect with each other. I'm also able to add a connection to the witness server from SQL Server Manager on the primary server. I've used the Configuration Manager on both servers to enabled Named Pipes and verify that IP traffic is enabled and using port 1433 by default.
What else could it be? Do I need any additional ports open for this to work? (The firewall rules are very restrictive, but I know traffic on the previously mentioned ports is explicitly allowed)
Caveats that are worth mentioning here:
Each server is in a different network segment
The servers don't use AD and aren't part of a domain
There is no DNS server configured for these servers, so I'm using the HOSTS file to map domain names to IP addresses (verified using telnet, ping, etc).
The firewall rules are very restrictive and I don't have direct access to tweak them, though I can call in a change if needed
Data1 and Data2 are using SQL Server 2008, Datawitness is using SQL Express 2005. All of them use the default instance (i.e. none of them are named instances)
After combing through blogs and KB articles and forum posts and reinstalling and reconfiguring and rebooting and profiling, etc, etc, etc, I finally found the key to the puzzle - an entry in the event log on the witness server reported this error:
Database mirroring connection error 2 'DNS lookup failed with error: '11001(No such host is known.)'.' for 'TCP://ABC-WEB01:7024'.
I had used a hosts file to map mock domain names for all three servers in the form of datax.mydomain.com. However, it is now apparent that the witness was trying to comunicate back using the name of the primary server, which I did not have a hosts entry for. Simply adding another entry for ABC-WEB01 pointing to the primary web server did the trick. No errors and the mirroring is finally complete.
Hope this saves someone else a billion hours.
I'd like to add one more sub answer to this specific question, as my comment on Chris' answer shows, my mirror was showing up as disconnected (to the witness) Apperently you need to reboot (or in my case i just restarded the service) the witness server.
As soon as i did this the mirror showed the Witness connection as Connected!
See: http://www.bigresource.com/Tracker/Track-ms_sql-cBsxsUSH/