First I try to explain my server environment.
I have two virtual servers, the host server is Ubuntu. The mailserver is Debian Squeeze installed with this tutorial: http://workaround.org/ispmail/squeeze.
Everything works nicely.
There is just one big mysterium which causes me hard work. I can not connect from my mail server to the mail server "mail.swisscom.com". My mail server is "mail.pixelwolf.ch". From the mail server of Swisscom I can not receive or send emails to my server (pixelwolf). From my server to Swisscom I can not receive or send messages.
Ok I tried the following things:
- DNS Check (OK, DNS can be resolved)
- Routing (OK, traceroute and mtr shows the correct routing)
- Sending/Receiving mails from others (OK, tested from 3 different mail servers)
- Telnet to mail.swisscom.com (NOT OK, there is a Connection timeout)
TCPdump shows the connection to mail.swisscom.com but no connection from Swisscom to Pixelwolf. On the exchange account of Swisscom there is a delay message and after 12 hours there is a "undeliverable" message. It says pixelwolf.ch has permanent fatal errors. On my side my mail server said there is a connection timeout and Postfix tries to deliver the mail in the next 5 days.
The first problem showed up yesterday at 3pm. The server is unmanaged and I even tried to resolve the problems with the hosting center hetzner.de and they said there is no error on their side. Swisscom said they can't look at the problem because the company is much too big (over 20000 employees).
So what can I do? My boss can't send me mails and I can't send him mails.
UPDATE: My server is not blacklisted on any spam blacklist like Spamhaus or Spamcop.