Editing Software setup for db-class (section)

==== Update firewall ====

By default iptables will not be allowing TCP port 3306 (default port for mysql server).

Confirm if 3306 is in iptables
<pre># # cat /etc/sysconfig/iptables | grep 3306
#</pre>

Add rule to allow TCP connections from particular local area network [you insert your IP address & subnet for your setup]
<pre># iptables -A INPUT -p tcp -s 192.168.1.0/24 -m state --state NEW -m tcp --dport 3306 -j ACCEPT</pre>

If you want to allow TCP connections from any network you can use this command
<pre># iptables -A INPUT -p tcp -m state --state NEW -m tcp --dport 3306 -j ACCEPT</pre>

'''NOTE: Use one of the rules above not both.'''

Save the iptables rules to make them persistent [RHEL/CentOS/Fedora Core support this command] 
<pre># /etc/init.d/iptables save
iptables: Saving firewall rules to /etc/sysconfig/iptables: [  OK  ]</pre>

Confirm new rule was added to configuration file 
<pre># cat /etc/sysconfig/iptables | grep 3306
-A INPUT -s 192.168.1.0/24 -p tcp -m state --state NEW -m tcp --dport 3306 -j ACCEPT</pre>

Restart iptables
<pre># service iptables restartiptables: Flushing firewall rules: [  OK  ]
iptables: Setting chains to policy ACCEPT: filter [  OK  ]
iptables: Unloading modules: [  OK  ]
iptables: Applying firewall rules: [  OK  ]</pre>

===== Trouble shooting firewall =====

You may need to move your rule above another rule that rejects your MySQL traffic. Use text editor to move your new rule above other rule in /etc/sysconfig/iptables

To quickly trouble shoot firewall issue simply disable firewall & test MySQL connection. If MySQL connectivity works then double check your firewall rules.

Disable IPtables: <code># service iptables stop</code>

Enable IPtables:  <code># service iptables start</code>

'''Enable iptables when you're done testing connection!!!'''