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troubleshooting Question

email thru IIS5.0 smtp relay triggers BAD HELO NO DNS status WHY?

Avatar of grant-ellsworth
grant-ellsworth asked on
Microsoft IIS Web ServerWindows Server 2003Email Protocols
21 Comments1 Solution616 ViewsLast Modified:
Hello, On a IIS5.0 I have an smtp relay for routing outbound email.  The outbound email is getting trappeed in spam filters for "bad helo no dns"  
Configuration :
1. IIS is running on a Windows 2003 server behind a NAT firewall.  
2. SMTP relay is set to relay only for computers on local  network.
3.  Router is using NAT - no transparent mapping external IPs - router supports one public IP address
4.  Server is behind the NATWall
5.  SMTP TCP Port 25 is open on firwall and is forwarded to WinServer 2003 which is hosting the IIS / SMTP Relay
6.  Inside lan I can telnet to the IIS SMTP relay and get the identifier displayed and enter commands
7.  Outside / from internet, telnet to roter's public ip on port 25 produces black screen - NO id string gets displayed and any attempt to key anything ends the application
Not all email is getting stomped as spam as most recipients do not have this agresssive detection set (bad helo etc)
Local email client is Outlook express equivalent

What do I need to do to geth the smtp relay to be recognized as a valid smtp relay so our emails aren't tomped as spam?
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