Tag Archives: IPTables

IPTables rules for MySQL

If iptables locks all incoming connections (INPUT DROP) and to add external access to MySQL, you need to add rules:

iptables -A INPUT -p tcp -m tcp --dport 3306 -j ACCEPT

To access only a particular network, for example 10.0.0.0/24:

iptables -A INPUT -s 10.0.0.0/24 -p tcp -m tcp --dport 3306 -j ACCEPT

To remove a rule, we’ll specify the same command, replacing -A with -D, for example:

iptables -D INPUT -p tcp -m tcp --dport 3306 -j ACCEPT

To view the list of rules, use the command:

sudo iptables -nvL

I note that in order to open external access, you also need to comment out the line “bind-address = 127.0.0.1” in the my.cnf configuration file.

If by default INPUT ACCEPT, we first specify which IPs are allowed access, and only the last rule is blocked by all the others:

/sbin/iptables -A INPUT -s 127.0.0.1 -p tcp --destination-port 3306 -j ACCEPT
/sbin/iptables -A INPUT -s 192.168.1.5 -p tcp --destination-port 3306 -j ACCEPT
/sbin/iptables -A INPUT -p tcp --dport 3306 -j DROP

For example, using nmap, you can check locally and externally whether the access is filtered:

nmap -p 3306 localhost
nmap -p 3306 192.168.1.5

See also:
Configuring IPTables
Other my articles about MySQL

IPTables rules for FTP server

To open access to the FTP server in IPTables, you need to add rules:

sudo iptables -A INPUT -p tcp --dport 21 -j ACCEPT
sudo iptables -A OUTPUT -p tcp --sport 20 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 1024:1030 -j ACCEPT

To only allow access to a particular network, for example 192.168.1.0/24:

sudo iptables -A INPUT -s 192.168.1.0/24 -p tcp --dport 21 -j ACCEPT
sudo iptables -A OUTPUT -p tcp --sport 20 -j ACCEPT
sudo iptables -A INPUT -s 192.168.1.0/24 -p tcp --dport 1024:1030 -j ACCEPT

To remove a rule, we’ll specify the same command, replacing -A with -D, for example:

sudo iptables -D INPUT -p tcp --dport 21 -j ACCEPT
sudo iptables -D OUTPUT -p tcp --sport 20 -j ACCEPT
sudo iptables -D INPUT -p tcp --dport 1024:1030 -j ACCEPT

To view the list of rules, use the command:

sudo iptables -nvL

1024-1030 – example ports for passive mode are specified in the FTP server configuration, for example for ProFTPd are specified in the /etc/proftpd/proftpd.conf file as follows:

PassivePorts 1024 1030

See also my articles:
Configuring IPTables
Active and passive FTP mode
Installing and Configuring Pure-FTPd in Ubuntu
Installing and Configuring ProFTPd in Ubuntu