I've installed a server with ISPConfig. It's just GREAT! Everything seems to be working well, except for incoming mails from outside. I may be wrong, but I think the problem comes from the fact that port 25 is closed from outside. I mean, on the server side it is open: I checked with netstat, and if I do telnet localhost 25 it works. I also checked the ISPConfig firewall to make sure port 25 is open. But if I try telnet from outside, it doesn't work. If I send emails to users from an outside account, they finally come back with a "Connection timed out" error. If think this is normal if indeed port 25 is closed. Am I wrong? If I'm right, the next question is: why is port 25 closed? How can I open it? BTW, I should also mention that I'm not using any port-forwarding (as I would do with my router at home) because the server is hosted in my university with its own public IP. Please, anyone has a suggestion? Anything I should check?
What's the value of inet_interfaces in /etc/postfix/main.cf? Please post the output of Code: iptables -L Can you make sure your university isn't blocking port 25?
Here it is: Code: inet_interfaces = all --> So far so good... Here it is: Code: Chain INPUT (policy DROP) target prot opt source destination DROP tcp -- anywhere loopback/8 ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED ACCEPT all -- anywhere anywhere DROP all -- BASE-ADDRESS.MCAST.NET/4 anywhere PUB_IN all -- anywhere anywhere PUB_IN all -- anywhere anywhere PUB_IN all -- anywhere anywhere DROP all -- anywhere anywhere Chain FORWARD (policy DROP) target prot opt source destination ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED DROP all -- anywhere anywhere Chain INT_IN (0 references) target prot opt source destination ACCEPT icmp -- anywhere anywhere DROP all -- anywhere anywhere Chain INT_OUT (0 references) target prot opt source destination ACCEPT icmp -- anywhere anywhere ACCEPT all -- anywhere anywhere Chain OUTPUT (policy ACCEPT) target prot opt source destination PUB_OUT all -- anywhere anywhere PUB_OUT all -- anywhere anywhere PUB_OUT all -- anywhere anywhere Chain PAROLE (11 references) target prot opt source destination ACCEPT all -- anywhere anywhere Chain PUB_IN (3 references) target prot opt source destination ACCEPT icmp -- anywhere anywhere icmp destination-unreachable ACCEPT icmp -- anywhere anywhere icmp echo-reply ACCEPT icmp -- anywhere anywhere icmp time-exceeded ACCEPT icmp -- anywhere anywhere icmp echo-request PAROLE tcp -- anywhere anywhere tcp dpt:ftp PAROLE tcp -- anywhere anywhere tcp dpt:ssh PAROLE tcp -- anywhere anywhere tcp dpt:smtp PAROLE tcp -- anywhere anywhere tcp dpt:domain PAROLE tcp -- anywhere anywhere tcp dpt:http PAROLE tcp -- anywhere anywhere tcp dpt:hosts2-ns PAROLE tcp -- anywhere anywhere tcp dpt:pop3 PAROLE tcp -- anywhere anywhere tcp dpt:https PAROLE tcp -- anywhere anywhere tcp dpt:ndmp PAROLE tcp -- anywhere anywhere tcp dpt:imap PAROLE tcp -- anywhere anywhere tcp dpt:imaps ACCEPT udp -- anywhere anywhere udp dpt:domain DROP icmp -- anywhere anywhere DROP all -- anywhere anywhere Chain PUB_OUT (3 references) target prot opt source destination ACCEPT all -- anywhere anywhere --> Anything wrong with it? --> If no other explanation can be found, that might the reason. I would have to ask...
Well, I had confirmation that port 25 is indeed blocked by the university! I've been told that such port blocking is more and more common, so if other users experience the same problem, check with your network administrator or ISP if they're not doing the same! Thank you for your help falko!
