iptables
@firewalls
Set up default DROP rule for eth0
iptables -P INPUT DROP
Allow existing connections to continue
iptables -A INPUT -i eth0 -m state --state ESTABLISHED,RELATED -j ACCEPT
Accept everything from the 192.168.1.x network
iptables -A INPUT -i eth0 -s 192.168.1.0/24 -j ACCEPT
Drop a single host
iptables -I INPUT -s 192.168.1.100 -j DROP
Allow connections from this host to 192.168.2.10
::
iptables -A OUTPUT -o eth0 -d 192.168.2.10 -j ACCEPT
Flush table
::
iptables --flush
Allow incoming HTTP
::
iptables -A INPUT -i eth0 -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eth0 -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT
Limit connections
::
iptables -A INPUT -p tcp --dport 80 -m limit --limit 25/minute --limit-burst 100 -j ACCEPT
Simple IP masquerading
::
echo "1" > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -o $EXT_IFACE -j MASQUERADE
Backup, reload iptables rules
::
iptables-save > ./file
iptables-restore < ./file
File location
::
/etc/sysconfig/iptables