Re: Request for help: Debian firewall, and maybe some kernel upgrade tips - KCLUG

13 Apr 2005


      ...
| Also. Is there any sort of firewall that is real
| easy to configure, something like this:
|
| [SuperEasyFirewall]
| Open=22,80,23
| Blocked=22.23.34.43:[22,80]
| Closed=EverythingElse
|
| I don't understand why a firewall config has to be
| four miles long and so dern complicated!
|
| -Jared
# clear the tables
iptables -F
# set the default for the INPUT chain to DROP
iptables -I INPUT -j DROP -i eth0
# allow established and related connections
iptables -I INPUT -j ACCEPT -i eth0 -m state --state ESTABLISHED,RELATED
# Allow ports 22,23,80
iptables -I INPUT -j ACCEPT -i eth0 -p tcp --dport 22
iptables -I INPUT -j ACCEPT -i eth0 -p tcp --dport 23
iptables -I INPUT -j ACCEPT -i eth0 -p tcp --dport 80
# Allow localhost connections
iptables -I INPUT -j ACCEPT -i lo
# Block this IP on port 22 and 80
iptables -I INPUT -j DROP -i eth0 -p tcp --dport 22 -s 22.23.34.43
iptables -I INPUT -j DROP -i eth0 -p tcp --dport 80 -s 22.23.34.43
Chris
Chris,
Thank you! I now understand what iptables are doing.
This helps a lot.
-Jared