How to configure iptables to use apt-get in a server?
- by segaco
I'm starting using iptables (newbie) to protect a linux server (specifically Debian 5.0). Before I configure the iptables settings, I can use apt-get without a problem. But after I configure the iptables, the apt-get stop working. For example I use this script in iptables:
#!/bin/sh
IPT=/sbin/iptables
## FLUSH
$IPT -F
$IPT -X
$IPT -t nat -F
$IPT -t nat -X
$IPT -t mangle -F
$IPT -t mangle -X
$IPT -P INPUT DROP
$IPT -P OUTPUT DROP
$IPT -P FORWARD DROP
$IPT -A INPUT -i lo -j ACCEPT
$IPT -A OUTPUT -o lo -j ACCEPT
$IPT -A INPUT -p tcp --dport 22 -j ACCEPT
$IPT -A OUTPUT -p tcp --sport 22 -j ACCEPT
$IPT -A INPUT -p tcp --dport 80 -j ACCEPT
$IPT -A OUTPUT -p tcp --sport 80 -j ACCEPT
$IPT -A INPUT -p tcp --dport 443 -j ACCEPT
$IPT -A OUTPUT -p tcp --sport 443 -j ACCEPT
# Allow FTP connections @ port 21
$IPT -A INPUT -p tcp --sport 21 -m state --state ESTABLISHED -j ACCEPT
$IPT -A OUTPUT -p tcp --dport 21 -m state --state NEW,ESTABLISHED -j ACCEPT
# Allow Active FTP Connections
$IPT -A INPUT -p tcp --sport 20 -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPT -A OUTPUT -p tcp --dport 20 -m state --state ESTABLISHED -j ACCEPT
# Allow Passive FTP Connections
$IPT -A INPUT -p tcp --sport 1024: --dport 1024: -m state --state ESTABLISHED -j ACCEPT
$IPT -A OUTPUT -p tcp --sport 1024: --dport 1024: -m state --state ESTABLISHED,RELATED -j ACCEPT
#DNS
$IPT -A OUTPUT -p udp --dport 53 --sport 1024:65535 -j ACCEPT
$IPT -A INPUT -p tcp --dport 1:1024
$IPT -A INPUT -p udp --dport 1:1024
$IPT -A INPUT -p tcp --dport 3306 -j DROP
$IPT -A INPUT -p tcp --dport 10000 -j DROP
$IPT -A INPUT -p udp --dport 10000 -j DROP
then when I run apt-get I obtain:
core:~# apt-get update
0% [Connecting to ftp.us.debian.org] [Connecting to security.debian.org] [Conne
and it stalls. What rules I need to configure to make it works.
Thanks
