> > Maybe, I'm not sure, some remote MTAs, for example smtp.navegalia.com, uses > > UDP connections. You can try "telnet smtp.navegalia.com 25" behind a > > firewall which filter the udp connection. > > Eh? > $ telnet smtp.navegalia.com 25 > Trying 212.73.32.155... > Connected to smtp.airtel.net. > Escape character is '^]'. > 220 ESMTP service > > It answers TCP, I know of no MTA (or MUA) that uses UDP...
Well, I have removed the iptables rule allowing the UDP/25 packets and it works OK. It seems you are right again. > If you're having firewall problems then most likely: > *) TCP port 25 is not allowed > *) TCP port 113 (AUTH) is not allowed (it should be REJECTED, a > DROP will result in some remote MTA timeouts as they try to > issue AUTH requests) I have added the iptables filter: iptables -A FORWARD -p tcp -d 194.224.7.3 --dport 112 -j REJECT -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
