Joseph Brennan wrote: > >It says a CNAME can be used, if it can be resolved. So sendmail > >resolves it. I don't see any problem there.
Yes, the CNAME will resolve, but Sendmail will rewite the user@cname to user@realname. Sendmails behaviour is explained with the confDONT_EXPAND_CNAMES option as follows: [False] If set, $[ ... $] lookups that do DNS based lookups do not expand CNAME records. This currently violates the published standards, but the IETF seems to be moving toward legalizing this. For example, if "FTP.Foo.ORG" is a CNAME for "Cruft.Foo.ORG", then with this option set a lookup of "FTP" will return "FTP.Foo.ORG"; if clear it returns "Cruft.FOO.ORG". N.B. you may not see any effect until your downstream neighbors stop doing CNAME lookups as well. It seems that RFC2821 legalised the use of CNAMEs and Sendmail should not rewrite it anymore (the information above seems to be out dated). Like I mentioned I can fix my sendmail behaviour with the confDONT_EXPAND_CNAMES option. I would however like to find proove that the behaviour of sendmail is still valid. The reason I don't want to implement confDONT_EXPAND_CNAMES is that I currently use this server to rewrite the sender domain on purpose for an internal server. _______________________________________________ NOTE: If there is a disclaimer or other legal boilerplate in the above message, it is NULL AND VOID. You may ignore it. Visit http://www.mimedefang.org and http://www.roaringpenguin.com MIMEDefang mailing list [email protected] http://lists.roaringpenguin.com/mailman/listinfo/mimedefang
