Relay denied problem only on replies to emails
Posted on 2003-03-18
We have a problem whereby some recipients of emails get an error NDR back when they try to reply to emails from our company. The NDR says…
"The recipient name is not recognized
The MTS-ID of the original message is: c=US;a= ;p=SHG;l=SAVNTMSE-030317125353Z-69175
MSEXCH:IMS:SHG:SHGNT:SAVNTMSE 3550 (000B09AA) 550 5.7.1 Unable to relay for email@example.com"
We are running exchange 2000 but we are not using our own virtual SMTP server. All our e-mail is manged via a separate SMTP server with our ISP. The set up is a bit complicated because we recently installed a gateway machine hanging off of the server that is connected to a BT ADSL line with a static IP. This was to allow all e-mail to go out via that rather than the ISDN connection that the main router is connected to (i.e to save on call charges).
We found that PCs that had Outlook 2000 installed worked fine using the SMTP server of the existing ISP (hotchilli.net), i.e. where the domain name is held, but Outlook 2002 would not send out via that SMTP server (you get a relay denied message). Fixed that problem by changing the outgoing SMTP server on the outlook 2002 machine to be mail.btinternet.com and added the username and password for the ADSL account.
That works a treat, however at least one recipient is complaining that when they try to reply to mail from our company they get this relay denied message. A new e-mail to us works fine, it's just replies that are the problem. The reply e-mail address is coming up correctly, so we're now a bit stuck for a solution.
I appreciate it's probably something the recipient needs to change but is there anything we can do our end, or what is causing the problem.
Any help would be much appreciated."