Hello all. I�m a bit stuck here. I have one firewall, that does nat, redirection and filtering. It has one public ip, two more interfaces with two subnets of private ips, lan and DMZ. I have a mail server in DMZ, doing smtp, pop3 and imap. I wrote the redirection rules on the firewall, to redirect all incoming stuff related to the mentioned services to the server in DMZ, that is to its private ip. I have the same set of rules for port 25, 110, 143. When i try to telnet public.ip.add.ress from outside, I connect just fine to my pop3 and imap ports, but I get no reply from smtp whatsoever. When I try to telnet to the private address from the DMZ or lan subnet, it works just fine. I figure, if my pop3 and imap work, why the hell is port 25 so problematic, and it ought to work as well. Then I red that there could be problems with MTU - disabled, got the same result. Then I opened virtually all on my firewall. Still no change. The log on the external interface of the firewall doesn�t show a thing about someone trying to connect to port 25 from outside, while simultaneously I not only get to see connections to ports 110 and 143, but I also can read my email from outside.
The mistery goes further. When I tried to send mails from my mail server located in DMZ, I failed, the connection timed out and the message goes to the deferred queue. However, when I try to send an email to , for example, [EMAIL PROTECTED] I get it just fine. What a misery. Does anyone have an idea why pf and/or smtp protocol behave in such a way, and how this could be solved? If it is worth, I am connected via adsl. The rules that I wrote have been discussed here a million times - just a standard set of rules that work for all but smtp. Oh, by the way, I can ssh into this mail server from outside without any problems. So, it is only the smtp issue. Much appreciated, your help. Pedja --
