NDR Spam

I have a SBS 2003 box hosting email with Exchange. Many of the users
are getting NDR reports with spam in them every few minutes. I have
Symantec Mail Agent for Exchange updated and running. Clients report no
virus problems.
I have a telneted to the mail server from the outside. The reply to
telnet xxx.xxx.xxx.xxx 25 is a different name than my mail server. I
type in the correct IP address and receive the wrong hostname. When I
test for open relay, it responds with the 250 ok instead of blocking. I
went through the Microsoft KB for closing an open relay. Default SMTP
and SmallBusiness SMTP set as they should be.
Is there a way to determine if the emails are originating elsewhere, if
the sender address was being spoofed. The mails that are going out are
coming from mydomain@mydomain which is not one of my email addresses.
Thanks,
Chris

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Relevant Pages

  • Re: NDR Spam
    ... are getting NDR reports with spam in them every few minutes. ... I have a telneted to the mail server from the outside. ... test for open relay, it responds with the 250 ok instead of blocking. ... SMTP and SmallBusiness SMTP set as they should be. ...
    (microsoft.public.windows.server.sbs)
  • RE: problem using pop3 in different organizations
    ... When Exchange is responsible for an e-mail domain, ... If a local recipient with that e-mail address does not exist, ... >> Then expand the administrative group that contains the mail server. ...
    (microsoft.public.windows.server.sbs)
  • RE: problem using pop3 in different organizations
    ... When Exchange is responsible for an e-mail domain, ... If a local recipient with that e-mail address does not exist, ... > recipients to the Internet service provider's mail server. ...
    (microsoft.public.windows.server.sbs)
  • Re: dcdiag - ... not responding to directory service requests
    ... a USN rollback problem so I demoted my mail server, ... server's dns entries so I deleted and created an identical record. ... If you had a complete system state and Exchange backup, ... This is a direct link to the Microsoft Public ...
    (microsoft.public.win2000.dns)
  • Re: E-mail
    ... > mail within the network. ... > but I maintain the mail server. ... specific configuration information to better help you out. ... is this a Microsoft Exchange server or another brand? ...
    (microsoft.public.win2000.dns)