Question : Hmailserver not receiving from Gmail and Yahoo

Dear Community,

I am having a strange problem.
I set up hmailserver 5 on a win2008 64bit server.
Everything is fine: I can send to all domains and my mail is not in spam. wonderful.
The problem is the receive (of course):
I can receive from almost every domain BUT Yahoo and Gmail.
I get a "connection timed out" NDR in the gmail account (yahoo doesnt specify, but in my logs it looks the same).

Additional facts:
1. I did telnet test - works perfectly
2. DNS and MXrecord tests - everything fine.
3. I have no SPAM, Firewall Antivirus or whatsoever activated. The server is on public IP.
4. In the log I see the ehlo from Gmail and then the little talk until my server says: OK, send DATA. then - nothing.
5 On Capsasoft I see that Gmail tries to send, since I can read the email on packetlevel.

I set TCP window to 0. (read that this sometims creates that problem).
I have no filtering (Cisco-problem).

After 3 weeks I simply don't know anymore what to do.

Any help is highly appreciated.

Thanks a lot

Additional Info: I tried also mailEnable Mailserver - same result.... so it is my network. But my exchangeserver works.
I have a router (draytek) and 2 WAN IPs setup. One for NAT and one for Routing to additional public IPs. Exchange is in the NAT part, hMail and MailEnable have public IPs.

I did the following test: I directed on the router (draytek vigor 2910) port 25 not to the exchange, but to the hMailserver. Suddenly he could receive from everyone. through the public IP he cannot.
Now I am really stuck.....

Answer : Hmailserver not receiving from Gmail and Yahoo

The problem was the ISP. I hate him. 3 weeks without sleep....