Hi, I am puzzled. I cannot receive or send email when I have IP table on, except to Yahoo.com.  I get bounded emails when trying to send.  As soon as I stop IPTables I start receiving emails. CentOS 6.4, Postfix, dovcott, Spamassassin, virtual host server running on my business cox account (no blocked ports). Router ports that are open 21,22,25,53,80,143,443,587. (port forwarding) IPTable config: # Generated by iptables-save v1.4.7 on Fri Mar 29 14:08:56 2013 *filter :INPUT DROP [0:0] :FORWARD DROP [0:0] :OUTPUT ACCEPT [4:432] -A INPUT -s 192.168.20.0/24 -p tcp -m tcp --dport 22 -j ACCEPT -A INPUT -s x.x.x.x/32 -p tcp -m tcp --dport 22 -j ACCEPT -A INPUT -s x.x.x.x/32 -p tcp -m tcp --dport 22 -j ACCEPT -A INPUT -p tcp -m tcp --dport 25 -j ACCEPT -A INPUT -p tcp -m tcp --dport 53 -j ACCEPT -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT -A INPUT -p tcp -m tcp --dport 143 -j ACCEPT -A INPUT -p tcp -m tcp --dport 443 -j ACCEPT -A INPUT -p tcp -m tcp --dport 587 -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT COMMIT # Completed on Fri Mar 29 14:08:56 2013 Thank you for any insight. Keith ------------------------ Keith Smith