I located the /etc/mysql/my.cnf file
I changed the bind-address
first to 0.0.0.0 I received a '111 Connection refused'
then I changed it to the instance I am trying to connect to It still says '111 Connection refused'
the firewall rule allows connection on port 3306 using internal ip so I dont know the problem. Thanks
It seems that you have already taken the necessary steps to connect to MySQL server from GCE your instance. Based on the Stackoverflow case here the recommendation to resolve this problem is to comment this line below (add # at the beginning of the line) in your my.cnf file:
skip-networking
Once done you need to restart MySQL service
sudo service mysql restart
On the GCP side, if you have allowed the IP ranges you want to use with the specified port(3306), it should work fine.
You can also use “nmap” command to verify if port 3306 is open on your GCE instance with MySQL installed.
GCP provides CloudSQL which is a managed MySQL instance. You can access CloudSQL from your GCE VM using private address. This feature reached beta recently. This link provides detailed information about using private IP to connect to your Cloud SQL instances.
Before configuring a Cloud SQL instance to use private IP, you need some steps to be taken. This document provides step by step instructions for configuring an instance to use private IP.
You can use 'netstat -tunlp | grep 3306' command to verify that the MYSQL process is running on port 3306.
This error can also occur when mysql user account does not accept connections from any IP addresses. It may still use localhost parameter to connect to the server. I would recommend adding a user with remote access or granting existing user access to remote sources. You can see this: link for the similar issue and follow the steps recommended there to resolve.
Apologies if this is in some way a duplicate - I couldn't find anything that covered this (at least in a way that I could understand made it similar).
Here's a basic diagram of my connections:
Laptop => SSH server 1 => SSH server 2 => MySQL (MariaDB)
I can use terminal to jump across to server 2 as per the usual methods:
ssh -t user#server1 ssh -p99 user#server2
Then, in the terminal, I can mysql -uroot -p as normal.
(connections amended to remove details, of course)
I have attempted a few different things to try and get a direct connection in DBeaver, but I can't seem to make it work with that extra ssh connection (inssheption - it's new to me). I've found, and have been playing with, Gnome Connection Manager to try and make this happen - I'm used to Win tools like Penguinet, which isn't available on Linux, but it does look to be capable.
I'm probably just out of my depth, but I am thinking that this should be simple - but I just can't get the hang of how to get this going.
I'm expecting that at some point I'll be able to connect to 127.0.0.1:1234 in DBeaver (SQL GUI), but I'm just struggling to make that happen.
Does anyone have a moment to advise the best method to daisy-chain the connections together?
Use port forwarding with SSH to bring remote port to your local machine.
ssh -L 1234:server1:1234 -t user#server1 ssh -L 1234:server2:1234 -p99 user#server2
Now you can connect to localhost:1234 and your connection will be forwarded to server2:1234. Just make sure that port 1234 on server1 and localhost are not in use.
From EC2 instance i-78a8df00, I'm trying to connect to RDS instance mysql.************.us-east-1.rds.amazonaws.com. They are both in the U.S. East region. I added the security group of EC2 instance (sg-********) to the RDS security group, but that didn't help. It appears to be a firewall/DNS issue as it is timing out when running this command:
ubuntu#ip-10-195-189-237:~$ mysql -h mysql.************.us-east-1.rds.amazonaws.com
ERROR 2003 (HY000): Can't connect to MySQL server on 'mysql.************.us-east-1.rds.amazonaws.com' (110)
I can connect to RDS instance fine from my local machine using the same line as above. I tried various forum solutions but those don't help.
I had similar problem, when I spun a new EC2 instance, but didn't change setting in RDS security group of inbound IP address allowed to connect to port 3306 of my RDS instance.
The confusing bit was an option in RDS dashboard, called Security Groups. You don't need it to solve the problem.
What you really need is:
Go to list of RDS instances
Click on the instance you are trying to connect
Click Security group rules section
This should open a new browser tab or window with details of security group.
Locate several tabs in bottom part, select Inbound rules tab and click Edit button.
Change value to the IP address of your EC2 instance or IPv4 CIDR blocks, e.g.
174.33.0.0/16
To get this value, you can either ssh into your instance and run ip addr or run EC2 Manager in browser and locate value of Private IPs in your instance details.
Additional information for people who might run into similar issues trying to connect to RDS or RedShift:
1) Check security groups
Verify the security group for the RDS instance allows access from the security group your source server belongs to (or its IP added directly if external to AWS). The security group you should be looking at is the one specified in the RDS instance attributes from the RDS console UI (named "security group").
NOTE: Database security groups might be different from AWS EC2 security groups. If your RDS instance is in classic/public EC2, you should check in the "database security group" section of the RDS UI. For VPC users, the security group will be an normal VPC security group (the name sg-xxx will be listed in the RDS instance's attributes).
2) Confirm DNS isn't an issue.
Amazon uses split DNS, so a DNS lookup external to AWS will return the public IP while a lookup internal to AWS will return a private IP. If you suspect it is a DNS issue, have you confirmed different IPs are returned from different availability zones? If different AZs get different IPs, you will need to contact AWS support.
3) Confirm network connectivity by establishing a socket connection.
Tools like tracepath and traceroute likely won't help since RDS currently drops ICMP traffic.
Test port connectivity by trying to establish a socket connection to the RDS instance on port 3306 (mysql, or 5432 for postgres). Start by finding the IP of the RDS instance and using either telnet or nc:
telnet x.x.x.x 3306
nc -vz x.x.x.x 3306
a) If your connection attempt isn't successful and immediately fails, the port is likely blocked or the remote host isn't running a service on that port. you may need to engage AWS support to troubleshoot further. If connecting from outside of AWS, try to connect from another instance inside AWS first (as your firewall might be blocking those connections).
b) If your connection isn't successful and you get a timeout, packets are probably being dropped/ignored by a firewall or packets are returning on a different network path. You can confirm this by running netstat -an | grep SYN (from a different CLI window/session while running and waiting for the telnet/nc command to timeout). Connections in the SYN state mean that you've sent a connection request, but haven't received anything back (SYN_ACK or reject/block). Usually this means a firewall or security group is ignoring or dropping packets.
Check to make sure you're not using iptables or a NAT gateway between your host and the RDS instance. If you're in a VPC, also make sure you allow egress/outbound traffic from the source host.
c) If your socket connection test was successful, but you can't connect with a mysql client (CLI, workbench, app, etc.), take a look at the output of netstat to see what state the connection is in (replace x.x.x.x with the actual IP address of the RDS instance):
netstat -an | grep x.x.x.x
If you were getting a connection established when using telnet or NC, but you see the 'SYN' state when using a mysql client, you might be running into an MTU issue.
RDS, at the time this is written, may not support ICMP packets used for PMTUD (https://en.wikipedia.org/wiki/Path_MTU_Discovery#Problems_with_PMTUD). This can be a problem if you're trying to access RDS or RedShift that's in a VPC from a classic ec2 instance via ClassicLink. Try lowering the MTU with the following, then testing again:
sudo ip link show
# take note of the current MTU (likely 1500 or 9001)
sudo ip link set dev eth0 mtu 1400
If the lower MTU worked, be sure to follow up with AWS customer support for help and mention that you are seeing an MTU issue while trying to connect to your RDS instance. This can happen if TCP packets are wrapped with encapsulation for tunneling, resulting in a lower usable MTU for packet data / payload. Lowering the MTU on the source server allows the wrapped packets to still fit under the limit.
If it didn't work, set your MTU back to it's default and engage AWS support for further troubleshooting.
While Mark's problem seemed to have something to do with multi-AZ routing & EC2 classic, I ran into this exact same problem today.
To fix it, I modified the Security Group that was created automatically with my RDS instance by adding the two private IP addresses from my EC2 instance.
This was a fairly obvious problem, but I'm new to AWS in general, so hopefully this is useful for others like myself.
Apparently, multi-AZ screws everything up. Since the default multi-AZ config placed my database in region us-east-1d, and my EC2 instance was in region us-east-1a, the DNS was not routing correctly. I re-created the RDS instance as non-multi-AZ, and made it live in us-east-1a, and all is happy.
If there are any super geniuses out there in regards to DNS routing on AWS with RDS, ELB, and multi-AZ capabilities, it would be pretty awesome to know how to do this, since this isn't documented anywhere in Amazon Web Service's documentation.
After struggling for 3 days I finally found why mine was not connecting ...
Add outbound rule on your EC2 instance for port 3306 and inbound rules on your RDS server on port 3306. The inbound value should be the security of the EC2 instance
Example:
Your EC2 security group is - sg.ec2
And RDS security group is - sg.rds
So go to edit outbound rules of sg.ec2 and add Custom TCP at port 3306 and destination to 0.0.0.0/0
Then, go to edit inbound rule of sg.rds and add an inbound rule at port 3306 and source as sg.ec2
I had the similar problem today when my EC2 instance suddenly lost access to RDS instance and Wordpress stopped working. The security groups were correct and I could even connect to MySQL from console on EC2 instance but not from PHP. For some reason restarting EC2 server helped me.
Looks like sometime between the last posting and this posting, Amazon fixed the DNS routing issue, because everything works fine now for multi-AZ rds...
Solution: I had to adjust the inbound rule of the RDS instance's security group to allow connections from the IP address of my EC2 instance.
Longer explanation: When creating an AWS RDS instance I selected the option to be able to connect to it via public IP address. In doing so I ASSUMED that I would then be able to connect to it from ANY IP Address, but that was not the case. Rather, when the instance got created/configured, it took the public IP address of my laptop and set the inbound rule of the RDS security group to only accept connections from that IP address. So I had to manually add a rule to allow incoming MYSQL/Aurora connections from IP address of the EC2 instance.
I ran into the same issue, I was not able to connect from EC2 instance to the RDS both resources in the same VPC and multi AZ setup.
The multi-AZ setup was not a problem for me.
I was missing only the OUTBOUND rule 3306 from my EC2 instance Security group, to my RDS Security group.
According to the Amazon doc, we should use:
PROMPT> mysql -h <endpoint> -P 3306 -u <mymasteruser> -p
where endpoint and mymasteruser(username) are from your RDS instance.
I solved that problem using IP public adress directly(of the endpoint) instead of the endpoint(****.us-east-1.rds.amazonaws.com).You can get the ip public address using "ping" command(ping ****.us-east-1.rds.amazonaws.com)
(I'm posting this question after the fact because of the time it took to find the root cause and solution. There's also a good chance other people will run into the same problem)
I have an RDS instance (in a VPC) that I'm trying to connect to from an application running on a classic EC2 instance, connected via ClassicLink. Security groups and DNS aren't an issue.
I am able to establish socket connections to the RDS instance, but cannot connect with CLI tools (psql, mysql, etc.) or DB GUI tools like toad or mysql workbench.
Direct socket connections with telnet or nc result in TCP connections in the "ESTABLISHED" state (output from netstat).
Connections from DB CLI, GUI tools, or applications result in timeouts and TCP connections that are stuck in the "SYN" state.
UPDATE: The root cause in my case was a problem with MTU size and EC2 ClassicLink. I've posted some general troubleshooting information below in an answer in case other people run into similar RDS connectivity issues.
Additional information for people who might run into similar issues trying to connect to RDS or RedShift:
1) Check security groups
Verify the security group for the RDS instance allows access from the security group your source server belongs to (or its IP added directly if external to AWS). The security group you should be looking at is the one specified in the RDS instance attributes from the RDS console UI (named "security group").
NOTE: Database security groups might be different from AWS EC2 security groups. If your RDS instance is in classic/public EC2, you should check in the "database security group" section of the RDS UI. For VPC users, the security group will be a normal VPC security group (the name sg-xxx will be listed in the RDS instance's attributes).
2) Confirm DNS isn't an issue.
Amazon uses split DNS, so a DNS lookup external to AWS will return the public IP while a lookup internal to AWS will return a private IP. If you suspect it is a DNS issue, have you confirmed different IPs are returned from different availability zones? If different AZs get different IPs, you will need to contact AWS support.
3) Confirm network connectivity by establishing a socket connection.
Tools like tracepath and traceroute likely won't help since RDS currently drops ICMP traffic.
Test port connectivity by trying to establish a socket connection to the RDS instance on port 3306 (mysql, or 5432 for postgres). Start by finding the IP of the RDS instance and using either telnet or nc (be sure to use the internal/private IP if connecting from within AWS):
telnet x.x.x.x 3306
nc -vz x.x.x.x 3306
a) If your connection attempt isn't successful and immediately fails, the port is likely blocked or the remote host isn't running a service on that port. you may need to engage AWS support to troubleshoot further. If connecting from outside of AWS, try to connect from another instance inside AWS first (as your firewall might be blocking those connections).
b) If your connection isn't successful and you get a timeout, packets are probably being dropped/ignored by a firewall or packets are returning on a different network path. You can confirm this by running netstat -an | grep SYN (from a different ssh session while waiting for the telnet/nc command to timeout).
Connections in the SYN state mean that you've sent a connection request, but haven't received anything back (SYN_ACK or reject/block). Usually this means a firewall or security group is ignoring or dropping packets.
It can also be a problem with NAT routing or multiple paths from multiple interfaces. Check to make sure you're not using iptables or a NAT gateway between your host and the RDS instance. If you're in a VPC, also make sure you allow egress/outbound traffic from the source host.
c) If your socket connection test was successful, but you can't connect with a mysql client (CLI, workbench, app, etc.), take a look at the output of netstat to see what state the connection is in (replace x.x.x.x with the actual IP address of the RDS instance):
netstat -an | grep x.x.x.x
If you were getting a connection established when using telnet or NC, but you see the 'SYN' state when using a mysql client, you might be running into an MTU issue.
RDS, at the time this is written, may not support ICMP packets used for PMTUD (https://en.wikipedia.org/wiki/Path_MTU_Discovery#Problems_with_PMTUD). This can be a problem if you're trying to access RDS or RedShift that's in a VPC from a classic ec2 instance via ClassicLink. Try lowering the MTU with the following, then testing again:
sudo ip link show
# take note of the current MTU (likely 1500 or 9001)
sudo ip link set dev eth0 mtu 1400
If the lower MTU worked, be sure to follow up with AWS customer support for help and mention that you are seeing an MTU issue while trying to connect to your RDS instance. This can happen if TCP packets are wrapped with encapsulation for tunneling, resulting in a lower usable MTU for packet data / payload. Lowering the MTU on the source server allows the wrapped packets to still fit under the MTU limit while passing through the tunneling gateway.
If it didn't work, set your MTU back to it's default and engage AWS support for further troubleshooting.
I use WampServer (Apache, PHP, MySQL) and have no problems when some kind of network adapter(wireless or lan) is connected (i.e. Local Area Connection has status connected) even if i am not connected to the internet (for example when i am connected to the router but that is not connected to the internet).
When there is no network connection, I get a php error like MySQL could not connect to 127.0.0.1 on port 3306.
Interestingly, telnet 127.0.0.1 3306 says that it could not connect to the port, even when the server and MySQL are running fine (i.e. when some kind of local area connection is connected).
So I turned off all kinds of firewall (antivirus and Windows) but still no difference in anything. And that is why this issue is quite puzzling.
Things I have already tried (will update this list along the way):
The skip-networking directive in my.ini.
You could modify your MySQL server and client configuration to connect to one another using a named pipe instead of a TCP/IP loopback connection. That way, the current state of the network connection should have less impact.
To do so, start the server with --enable-named-pipe or the corresponding config file setting, and execute the client with --pipe or --protocol=PIPE. Similar configurations should be available for your PHP connector as well. It may depend on which library you use there, and whether or not it will take the mentioned configuration settings from the my.ini file (settings without leading -- there).