Relaying Not Allowed errors
Posted on 2006-11-08
It appears that some e-mail is being rejected by my SMTP server (Windows 2003), returns the 550 Relaying Not Allowed message. The majority of mail DOES go through, but a fair percentage is not due to this error.
Strangely enough, though, all mail is generated in the same way via ASP pages. I'm using ASPmail (Persits Software) which is configured to relay through smtp.bbdesign.com on port 25. DNS for smtp.bbdesign.com resolves to 22.214.171.124. From there, the SMTP server in IIS takes over.
When I view properties for the SMTP server, the IP address is set to an internal IP, 192.168.0.22. Relaying is allowed on 127.0.0.1, 192.168.0.20, 192.168.0.21, and 192.168.0.22. Masquerade domain is smtp.bbdesign.com. Fully-qualified domain name is blade4.bbdesign.com which resolves to 126.96.36.199.
I'm guessing there is a setting somewhere in this that I don't have quite right. I can't understand why only SOME mail is being rejected, though, as all mail is sent via nearly identical code.