Why can't I telnet to mysql port 3306?
Linode
Linode Staff
I have configured in my.cnf and turned off the firewall but it doesn't work. I just created 3 VPS using CentOS 8, seems to have the same problem.
1 Reply
jcardillo
Linode Staff
If you're trying to reach mysql over port 3306 from an external location, then yes, you'll need change the bind address in my.cnf, similar to what's outlined here:
https://serverfault.com/a/586656
Try to add bind-address = 0.0.0.0 to your [mysqld] section of your my.cnf and restart mysqld.
/etc/mysql/mysql.conf.d/mysqld.cnf
I just tested this out and it worked successfully. You mentioned you did this, but just to confirm: Add bind-address = 0.0.0.0, like it mentions, and also comment out bind-address = 127.0.0.1 by placing the # in front:
[mysqld]
bind-address = 0.0.0.0
# bind-address = 127.0.0.1
Then after restart mysql with sudo systemctl restart mysql, you should be able to telnet from an external server.
telnet 192.53.115.99 3306
Trying 192.53.115.99...
Connected to 192-53-115-99.ip.linodeusercontent.com.
Escape character is '^]'.
nmap -Pn -p3306 192.53.115.99
Starting Nmap 7.92 ( https://nmap.org ) at 2021-11-26 12:36 EST
Nmap scan report for 192-53-115-99.ip.linodeusercontent.com (192.53.115.99)
Host is up (0.39s latency).
PORT STATE SERVICE
3306/tcp open mysql
Nmap done: 1 IP address (1 host up) scanned in 0.51 seconds