I have an old mail server that I recently replaced.  The replacement is delivering mail as expected, but there is an odd quirk.  I have a variety of aliases that deliver mail to a list of people.  When user@domain.com sends an e-mail via Outlook to list@domain.com, there is a mapping for that Mail-User to an external address called list@mail.domain.com, so the To: gets rewritten and delivered to our mail server.  When newserver.domain.com gets the message, it accepts it and delivers it, but rewrites the To: header to list@newserver.domain.com.The issue with this is that it breaks the reply-to because it expects @domain.com and @mail.domain.com. How can I prevent this from happening? I have a CNAME in place that mail.domain.com points to newserver.domain.com, which makes me think it is mapping it from DNS somehow.  Can I prevent this, or at least force it to use mail.domain.com or domain.com instead of newserver?Example of the sendmail -bt /try esmtp test:> /try esmtp list@mail.domain.comTrying envelope recipient address list@mail.domain.com for mailer esmtpcanonify           input: list @ mail . domain . comCanonify2          input: list < @ mail . domain . com >Canonify2        returns: list < @ newserver . domain . com . >canonify         returns: list < @ newserver . domain . com . >2                  input: list < @ newserver . domain . com . >2                returns: list < @ newserver . domain . com . >EnvToSMTP          input: list < @ newserver . domain . com . >PseudoToReal       input: list < @ newserver . domain . com . >PseudoToReal     returns: list < @ newserver . domain . com . >MasqSMTP           input: list < @ newserver . domain . com . >MasqSMTP         returns: list < @ newserver . domain . com . >EnvToSMTP        returns: list < @ newserver . domain . com . >final              input: list < @ newserver . domain . com . >final            returns: list @ newserver . domain . comRcode = 0, addr = list@newserver.domain.com
Sendmail is canonicalizing domain name from CNAME
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