I wanna modify /etc/resolv.conf to change the DNS server.
my new DNS configuration:
$ cat /etc/resolv.conf
nameserver 10.200.4.101
search za.tryhackme.com
my tests:
$ ping 10.200.4.101
PING 10.200.4.101 (10.200.4.101) 56(84) bytes of data.
64 bytes from 10.200.4.101: icmp_seq=1 ttl=127 time=20.2 ms
$ nslookup ntlmauth.za.tryhackme.com
Server: 10.200.4.101
Address: 10.200.4.101#53
Name: ntlmauth.za.tryhackme.com
Address: 10.200.4.201
but
dig
;; communications error to 10.200.4.101#53: timed out
;; communications error to 10.200.4.101#53: timed out
;; communications error to 10.200.4.101#53: timed out
; <<>> DiG 9.18.7-1-Debian <<>>
;; global options: +cmd
;; no servers could be reached
$ ping ntlmauth.za.tryhackme.com
ping: ntlmauth.za.tryhackme.com: Nom ou service inconnu
I don't understand why with this configuration, I am not able to use the DNS with Ip adress 10.200.4.201.
Related
I followed this tutorial to connect qmp-shell to a QEMU VM instance.
1. Start QMP on a unix socket
# qemu-system-aarch64 -M virt -qmp unix:./qmp-sock,server,wait=off
2. Run the script
# qmp-shell ./qmp-sock
3. You should get the following prompt
(QEMU)
But step 2 gives below error:
ERROR: Couldn't connect to ./qmp-sock: Failed to establish connection: [Errno 2] No such file or directory
What could be wrong?
I am trying to connect to a MySQL RDS instance in AWS with Apache NiFi on Linux Ubuntu.
The MySQL database is behind a SSH tunnel which is working in a dedicated terminal. The MySQL database is accessible through another Linux terminal.
$ ssh -i /home/bernardo/.ssh/sshbernardo3.pem -N \
-L 33061:<db_name>.<id>.eu-west-1.rds.amazonaws.com:3306 \
<user>#<ip_address> -p <port>
I have uploaded and unzipped the JDBC driver from https://downloads.mysql.com/archives/c-j/
The file java.sql.Driver is located in the directory /usr/share/java/META-INF/services in Linux
I have installed the jdbc connector in Linux and set up the user to use JDBC
$ sudo apt-get install libmysql-java
$ cd /home/bernardo
$ gedit .bashrc
Added the following lines at the end of the file:
# Setting up the user to use JDBC
CLASSPATH=$CLASSPATH:/usr/share/java/mysql-connector-java-8.0.26.jar
export CLASSPATH
Then source it:
$ source .bashrc
In NiFi I have used a DBCPConnectionPool1.15.2 controller service which is configured as follows:
• Database Connection URL: jbdc:mysql://127.0.0.1:33061/<db_name>
• Database Driver Class Name: java.sql.Driver
• Database Driver Location: /usr/share/java/META-INF/services
• Database User: <db_user>
• Password: <db_password>
When enabling the controller service, I get the following error:
StandardControllerServiceNode[service=DBCPConnectionPool[id=2440f624-017e-1000-9467-8bb12dda6ca6],
name=<controller_service_name>, active=true] Failed to invoke
#OnEnabled method due to java.lang.NoSuchMethodException:
java.sql.Driver.() causes: java.lang.InstantiationException:
java.sql.Driver causes:
org.apache.nifi.processor.exception.ProcessException: Creating driver
instance is failed: Creating driver instance is failed
Any hint?
This is the SW I have installed:
Linux Ubuntu 18.04.6 in VirtualBox 6.1 on top of Windows 10 Pro
openjdk version "11.0.13" 2021-10-19
javac 11.0.13
nifi-1.15.2
Thanks,
Bernardo
EDITED on 2022 January 6 08:50 UTC
I have made the following changes to the DBCPConnectionPool1.15.2 controller service configuration:
• Database Driver Class Name: com.mysql.cj.jdbc.Driver
• Database Driver Location: /usr/share/java/mysql-connector-java-8.0.26.jar
The other parameters are not changed:
• Database Connection URL: jbdc:mysql://127.0.0.1:33061/<db_name>
• Database User: <db_user>
• Password: <db_password>
The file mysql-connector-java-8.0.26.jar is in /usr/share/java
Also:
$ cat /usr/share/java/META-INF/services/java.sql.Driver
com.mysql.cj.jdbc.Driver
And:
$ netstat -nplt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:33061 0.0.0.0:* LISTEN 4873/ssh
tcp6 0 0 ::1:33061 :::* LISTEN 4873/ssh
Still I get an error (a new error this time):
causes: org.apache.nifi.processor.exception.ProcessException: No suitable driver for the given Database Connection URL
Permissions to access the driver jar file:
bernardo#BDi-laptop:/usr/share/java$ ls -l
-rwxrwxr-- 1 bernardo bernardo 2462344 gen 4 19:01 mysql-connector-java-8.0.26.jar
EDITED on 2022 January 6 10:21 UTC
Added the CLASSPATH variable also in /etc/environment
bernardo#BDi-laptop:/usr/share/java$ echo $CLASSPATH
.:/usr/share/java/mysql-connector-java-8.0.26.jar:/usr/share/java/mysql-connector-java-8.0.26.jar
EDITED on 2022 January 7 09:08 UTC
I thought it could be an issue related to the driver version so I re-installed the jdbc driver. I have cleaned /home/bernardo/Download and /usr/share/java from the old sql related files. Then I have done the installation again.
Install the jdbc connector
$ sudo apt-get install libmysql-java
The .jar file is in /usr/share/java/mysql-connector-java-5.1.45.jar
Unpack the .jar file
$ sudo jar xvf /usr/share/java/mysql-connector-java-5.1.45.jar
To find the driver class name, open /usr/share/java/META-INF/services/java.sql.Driver
$ cat /usr/share/java/META-INF/services/java.sql.Driver
com.mysql.jdbc.Driver
com.mysql.fabric.jdbc.FabricMySQLDriver
The driver class name is: com.mysql.jdbc.Driver
This is the updated configuration in the DBCPConnectionPool1.15.2 controller service in Apache Ni-Fi:
• Database Driver Class Name: com.mysql.jdbc.Driver
• Database Driver Location: /usr/share/java/mysql-connector-java-5.1.45.jar
• Database Connection URL: jbdc:mysql://127.0.0.1:33061/<db_name>
• Database User: <db_user>
• Password: <db_password>
I have obtained the same result:
causes: org.apache.nifi.processor.exception.ProcessException: No suitable driver for the given Database Connection URL
Then I checked if the problem was in the SSH tunnel.
$ netstat -nplt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:33061 0.0.0.0:* LISTEN 4497/ssh
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN -
tcp6 0 0 ::1:33061 :::* LISTEN 4497/ssh
$ cat /proc/4497/status
Name: ssh
State: S (sleeping)
The SSH process is in sleeping state.
In a separate terminal I accessed the remote MySQL database:
$ mysql -u <db_user> -p -h 127.0.0.1 -P 33061
Finally, I tried to connect to my local mysql database in my local Linux instance by using the following Ni-Fi settings:
• Database Driver Class Name: com.mysql.jdbc.Driver
• Database Driver Location: /usr/share/java/mysql-connector-java-5.1.45.jar
• Database Connection URL: jbdc:mysql://127.0.0.1:3306/<local_db_name>
• Database User: <local_db_user>
• Password: <local_db_password>
I have obtained the same result:
causes: org.apache.nifi.processor.exception.ProcessException: No suitable driver for the given Database Connection URL
Still, in a separate Linux terminal I am able to access the local mysql database:
$ mysql -u <local_db_user> -p -h 127.0.0.1 -P 3306
EDITED on 2022 January 10 11:58 UTC
Corrected a typo in Ni-Fi controller service configuration:
• Database Connection URL: jdbc:mysql://127.0.0.1:33061/<db_name>
Controller service problem solved!
Thanks!
EDITED on 2022 January 12 08:26 UTC
I am still getting connectivity problems. I managed to enable the controller service but, when I run the processor QueryDatabaseTable, I get the following error: Cannot create PoolableConnectionFactory - Communications link failure
QueryDatabaseTable[id=017e1003-c2d8-14cf-4e34-feee76411595] Unable to execute SQL select query SELECT * FROM periodic_measurements_test due to java.sql.SQLException: Cannot create PoolableConnectionFactory (Communications link failure
The last packet successfully received from the server was 0 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.): javax.net.ssl.SSLHandshakeException: No appropriate protocol (protocol is disabled or cipher suites are inappropriate)
↳ causes: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 0 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.
↳ causes: java.sql.SQLException: Cannot create PoolableConnectionFactory (Communications link failure
The last packet successfully received from the server was 0 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.)
↳ causes: org.apache.nifi.processor.exception.ProcessException: java.sql.SQLException: Cannot create PoolableConnectionFactory (Communications link failure
The last packet successfully received from the server was 0 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.)
The processor configuration is default except for:
• Database Connection Pooling Service: < DBCPConnectionPool controller service name >
• Database Type: MySQL
• Table Name: periodic_measurements_test
The controller service configuration is still:
• Database Connection URL: jdbc:mysql://127.0.0.1:33061/<db_name>
• Database Driver Class Name: com.mysql.jdbc.Driver
• Database Driver Location: /usr/share/java/mysql-connector-java-5.1.45.jar
• Database User: <db_user>
• Password: <db_password>
The SSH tunnel seems to be fine:
netstat -nplt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:33061 0.0.0.0:* LISTEN 29483/ssh
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN -
tcp 0 0 127.0.0.1:8443 0.0.0.0:* LISTEN -
And in Linux terminal I can still access the MySQL database thorough CLI:
$ mysql -u <db_user> -p -h 127.0.0.1 -P 33061
And I get the same result when I try to fetch data from the MySQL database in my local Linux instance.
Finally, I managed to fix the issue. It was related to the version of the jdbc driver.
I did the following:
In Linux browser go to https://dev.mysql.com/downloads/connector/j/
Select
• Ubuntu Linux
• 18.04
Download
In a CLI terminal go to the Downloads directory
$ cd /home/bernardo/Downloads
Unpack the deb file
$ sudo dpkg -i mysql-connector-java_8.0.26-1ubuntu18.04_all.deb
Check where is the connector location in the file system
$ dpkg -L mysql-connector-java | fgrep jar
/usr/share/java/mysql-connector-java-8.0.26.jar
Clean /usr/share/java from the previous jdbc driver
$ sudo rm mysql-connector-java-5.1.45.jar
$ sudo rm -r com
$ sudo rm -r META-INF/
Install the connector: unpack the .jar file
$ sudo jar xvf /usr/share/java/mysql-connector-java-8.0.26.jar
To find the driver class name, open /usr/share/java/META-INF/services/java.sql.Driver
$ cat /usr/share/java/META-INF/services/java.sql.Driver
com.mysql.cj.jdbc.Driver
The driver class name is: com.mysql.jdbc.Driver
Restart Apache Ni-Fi
Modify the configuration of the controller service with:
• Database Driver Class Name: com.mysql.cj.jdbc.Driver
• Database Driver Location: /usr/share/java/mysql-connector-java-8.0.26.jar
So I tried to run the following
sudo certbot certonly --nginx --dry-run -d subdomain.domain.com -d www.subdomain.domain.com
That gave me a DNS problem, however, it worked when running
sudo certbot certonly --nginx --dry-run -d subdomain.domain.com
Am I missing something in my DNS records?
I have sucessfully run
sudo certbot certonly --nginx --dry-run -d domain.com -d www.domain.com
Do I need to make a specific DNS record for the ´´www´´ part if I use subdomains?
Edit
Result of running ´´dig subdomain.domain.com´´
; <<>> DiG 9.11.5-P4-5.1ubuntu2.1-Ubuntu <<>> subdomain.domain.co.uk
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 45932
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;subdomain.domain.co.uk. IN A
;; ANSWER SECTION:
subdomain.domain.co.uk. 1800 IN A xxx.yyy.aa.dd
;; Query time: 88 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Fri Feb 07 11:24:26 UTC 2020
;; MSG SIZE rcvd: 64
Answer
Create an type A entry with the host ´´www.subdomain´´ and you're good
Adding proper answer from the question:
Create an type A entry with the host "www.subdomain" and you're good
I'd add to wait anywhere between 5 minutes to an hour for the record to take effect and for certbot to be able to see it, from my experience.
In my case I didn't add www to my domain
add A record pointing to server
www.mydomain.com
Al together you need only two A records in domain pointing to your server ip with and without www
mydomain.com
Hope this helps !!!
If you are using subdomain than for the subdomain you dont need www.
Modified command would look something like below:
sudo certbot certonly --nginx --dry-run -d subdomain.com -d subdomain.com
I forget to add www A record in my godaddy DNS settings
You May try this one hope for best...
I cannot build pods in OKD as Github cannot be resolved and the build fails.
The error:
Cloning "https://github.com/MeMyselfI/okd-hello-world " ...
error: fatal: unable to access 'https://github.com/MeMyselfI/okd-hello-world/': Could not resolve host: github.com; Unknown error
How OKD is started:
sudo oc cluster up --routing-suffix=192.168.2.20.xip.io --public-hostname=192.168.2.20
OC client version:
me#server:~$ sudo oc version
oc v3.11.0+0cbc58b
kubernetes v1.11.0+d4cacc0
features: Basic-Auth GSSAPI Kerberos SPNEGO
ping from SSH prompt:
me#server:~$ ping github.com
PING github.com (192.30.253.113) 56(84) bytes of data.
64 bytes from lb-192-30-253-113-iad.github.com (192.30.253.113): icmp_seq=1 ttl=52 time=33.4 ms
64 bytes from lb-192-30-253-113-iad.github.com (192.30.253.113): icmp_seq=2 ttl=52 time=34.0 ms
ping from local, manually launched, Docker container:
me#server:~$ sudo docker exec -it hwnodemongo_web_1 /bin/bash
root#7c2db2faacf7:/usr/src/app# ping github.com
PING github.com (192.30.253.112) 56(84) bytes of data.
64 bytes from lb-192-30-253-112-iad.github.com (192.30.253.112): icmp_seq=1 ttl=52 time=28.3 ms
64 bytes from lb-192-30-253-112-iad.github.com (192.30.253.112): icmp_seq=2 ttl=52 time=27.4 ms
Output of resolv.conf
me#server:~$ cat /etc/resolv.conf
nameserver 8.8.8.8
dnsmasq is running:
dnsmasq 1479 0.0 0.0 51580 376 ? S 12:07 0:00 /usr/sbin/dnsmasq -x /run/dnsmasq/dnsmasq.pid -u dnsmasq -7 /etc/dnsmasq.d,.dpkg-dist,.dpkg-old,.dpkg-new --local-service --trust-anchor=.,19036,8,2,49aac11d7b6f6446702e54a1607371607a1a41855200fd2ce1cdde32f24e8fb5 --trust-anchor=.,20326,8,2,e06d44b80b8f1d39a95c0b0d7c65d08458e880409bbc683457104237c7f8ec8d
dig from SSH:
me#server.com:~$ dig github.com
; <<>> DiG 9.11.3-1ubuntu1.5-Ubuntu <<>> github.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 20999
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;github.com. IN A
;; ANSWER SECTION:
github.com. 59 IN A 192.30.253.113
github.com. 59 IN A 192.30.253.112
;; Query time: 46 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Fri Apr 05 13:23:47 ADT 2019
;; MSG SIZE rcvd: 71
Update:
I redid the install on another machine. I used oc cluster up (without any other parameters) and got the same results (by accessing localhost:8443/console).
I am setting up a reverse tunnel from localhost (win7) to remoteServer (Debian). On localhost I run:
plink.exe -R 12345:localhost:22 username#remoteServer.com.
But when I try to connect back from RemoteServer to localhost I an error:
root#remoteServer:~# ssh -v -p 12345 127.0.0.1
OpenSSH_6.0p1 Debian-4, OpenSSL 1.0.1e 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to 127.0.0.1 [127.0.0.1] port 12345.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/id_rsa type -1
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: identity file /root/.ssh/id_ecdsa type -1
debug1: identity file /root/.ssh/id_ecdsa-cert type -1
ssh_exchange_identification: Connection closed by remote host
root#remoteServer:~#
I have enabled GatewayPorts yes in sshd_config and restarted sshd.
I run cmd.exe with Admin rights.
solved. Needed to install SSH server on localhost (win7). plink.exe is just a client.