venerdì 20 dicembre 2013

CentOS Firewall Configuration

INTRODUCTION

I wanted to enable all the incoming traffic from the local network, so I added this line before the REJECT statements:
 -A INPUT -s 192.168.1.0/255.255.255.0 -j ACCEPT
there are many other possibilites for a more fine-tuned configuration, see:
 man 8 iptables

EXAMPLE

[root@centoshost /]# cat /etc/sysconfig/iptables
# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -s 192.168.1.0/255.255.255.0 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT
[root@centoshost /]# /etc/init.d/iptables restart
iptables: Flushing firewall rules:                         [  OK  ]
iptables: Setting chains to policy ACCEPT: filter          [  OK  ]
iptables: Unloading modules:                               [  OK  ]
iptables: Applying firewall rules:                         [  OK  ]
[root@centoshost /]#