[root at hwdltsaloli ~]# cat /etc/sysconfig/iptables # Firewall configuration written by system-config-securitylevel # Manual customization of this file is not recommended. *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :RH-Firewall-1-INPUT - [0:0] -A INPUT -j RH-Firewall-1-INPUT -A FORWARD -j RH-Firewall-1-INPUT -A RH-Firewall-1-INPUT -i lo -j ACCEPT -A RH-Firewall-1-INPUT -p icmp --icmp-type any -j ACCEPT -A RH-Firewall-1-INPUT -p 50 -j ACCEPT -A RH-Firewall-1-INPUT -p 51 -j ACCEPT -A RH-Firewall-1-INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT -A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited COMMIT [root at hwdltsaloli ~]# lsof -i:50 [root at hwdltsaloli ~]# lsof -i:51 [root at hwdltsaloli ~]# /etc/services says: re-mail-ck 50/tcp # Remote Mail Checking Protocol re-mail-ck 50/udp # Remote Mail Checking Protocol la-maint 51/tcp # la-maint 51/udp # IMP Logical Address Maintenance Google turns up RMCP is a simple lightweight DP protocol for checking if you have mail on a server A quick Google search failed to turn up what is "IMP Logical Address Maintenance" Why is this in the default iptables configuration? Thanks, Aleksey