Yet another “can't connect to MySQL over the network” question - but i seriously tried everything

Question

I was left with the easy task of installing moodle.

I am VPNing to 2 servers, one for the database and the other apache/php

server 1 must connect over LAN to the mySQL db on server 2

1. I added a user with following priveleges : +---------------+------------+ | host | user | +---------------+------------+ | % | mir | | 10.10.40.15 | mir | | x.x.x.x | mir |
   | localhost | mir |

2. Disabled firewall temporary

3. made sure that my username/password combinations are correct, flushed priveleges, restarted mysqld

4. i wnt to /etc/my.cnf .. if i try to add the port=3306 bind-address=10.10.40.15 or anything that is different from 0.0.0.0 or 127.0.0.1 - mysql wouldn't restart

5. i read and tried many forums and pages and asked friends for tips but nothing works

So my question to you :

• are there any networking extensions that need to be installed for mysql, how do i know nothing is missing from the installation
• any troubleshooting tips, any idea how to fix this, any step by step check list, am i missing something simple/stupid, please anything that comes to mind, let me know

Appreciate your feedback on this friday night stuck at work :P

Answer 1

the problem was not from the mysql side, it was rather from the php/apache server all i had to do was "setsebool -P httpd_can_network_connect=1

obviously there was a problem getting connections go out of the server that should request.

it made me waste more time than i should .. so i thought i would leave a comment to document a possible fix

Answer 2

1. Is it listetning on any port?

netstat -nap | grep -i mysql

1. If it is - is there any visible traffic from your client side?

tcpdump -i [interface_name] -tnn host [client_ip] and port [mysql_port_number]

1. If there is traffic... are there any responses send back??

tcpdump -i [interface_name] -tnn host [client_ip]

Answer 3

Pity you don't describe where exactly the connection broke or any error message. So here i try to put my general troubleshooting steps (apology if this is too n00b-minded):

1. make sure your web server can ping db server - if necessary - make sure the firewall allowing this (icmp and 3306 later on)
2. if 1 is ok, make sure web server can telnet to mysql's port in the db server.
3. if 2 is ok, make sure you can login using any other username/password (open any from any host, or use root username for quick test)

Which of those 3 you stuck with - and we'll go deeper...

Answer 4

thanks guys for feedback, currently when i

mysql -u mir -h 10.10.40.15 -p Enter password: ERROR 2003 (HY000): Can't connect to MySQL server on '10.10.40.15' (111)

but when i

mysql -u mir -p Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 2 Server version: 5.0.77 Source distribution

when i

telnet> open 10.10.40.13 3306 Trying 10.10.40.13... Connected to 10.10.40.13 (10.10.40.13). Escape character is '^]'. 4 5.0.77dAWsZLLz,Aq;m6cn$`=NOConnection closed by foreign host.

as for the netstat , here is output

netstat -nap | grep -i mysql tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 16698/mysqld
unix 2 [ ACC ] STREAM LISTENING 264736 16698/mysqld /var/lib/mysql/mysql.sock

for the tcp dump 1403 packets captured 1404 packets received by filter 0 packets dropped by kernel

i can ping the both addresses

any further ideas - really thanks for the feedback

Answer 5

Is SELinux enabled?