Iptables are cool and there are plenty of iptables guides and best practices out there. I’m not adding to the endless list of x common/best/cutest iptables topics. I’m just sharing my logging chain. Most people wanne log and drop, I wanted to log & accept. When working with offsite ip addresses you have no clue who is doing what, so storing some connection is good practice I believe. See here my awesome iptables ! Remarks are welcome !
# chain ACCEPT_LOG iptables -N ACCEPT_LOG iptables -A ACCEPT_LOG -j LOG --log-level 6 --log-prefix ':accept_log:' iptables -A ACCEPT_LOG -j ACCEPT # chain ACCEPT_LIMIT_LOG iptables -N ACCEPT_LIMIT_LOG iptables -A ACCEPT_LIMIT_LOG -m limit --limit 2/min -j LOG --log-level 6 --log-prefix ':accept_limit_log:' iptables -A ACCEPT_LIMIT_LOG -j ACCEPT # internal iptables -A INPUT -i lo -j ACCEPT # this is me, I trust me. iptables -A INPUT -p tcp -s 123.456.789.0 --dport 22 -j ACCEPT # allow ping iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT # I don't trust these guys but they need acces iptables -A INPUT -p tcp -s 666.666.666.666 --dport 80 -j ACCEPT_LOG -m comment --comment "Evil within" # these guys I trust more iptables -A INPUT -p tcp -s 126.96.36.199 --dport 80 -j ACCEPT_LIMIT_LOG # existing connections iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT # defaults iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT ACCEPT