On Mon, Jul 13, 2009 at 1:47 PM, Victor Duchovni<victor.ducho...@morganstanley.com> wrote: >> Don't use a CNAME in a mail address.
Why not? After all, how would you handle vhosts if you can't send as the CNAME record? > Sendmail often rewrites these. Postfix typically leaves CNAME domains > alone. The OP should avoid these, but otherwise, should find out *where* > along the delivery path the CNAME is replaced with the underlying name. I'm the OP. Based on the data I have, I believe that what goes into postfix uses the CNAME but what comes out is using the A record. I do have a little doubt, though, as the /var/log/maillog file shows "w...@atlas.cairodurham.org" connecting to postfix. If I "grep cairo main.cf*" and "grep atlas main.cf*", I don't see anything that should be rewriting this. I just tried a test with "telnet localhost 25" to be sure about this. That test appears to have worked out the way that I want. IOW, that it came from local_u...@cns.cairodurham.org. This gave me some doubts. However, when I change DNS so that both atlas.cairodurham.org and cns.cairodurham.org are A records (and the reverse DNS points to atlas) and try to send email from Request Tracker again, I find that it works the way that I want. So its caused by some combination of factors which includes the CNAME and Request Tracker. (Remember, using telnet to manually build and send a message sent it as cns.cairodurham.org before the DNS changed.) Any reason I shouldn't leave the DNS like this? Also, that question about virtual hosting of several email domains was not rhetorical. How is a sysadmin supposed to configure their DNS for such a thing? Thanks, Jaime -- Network Administrator Cairo-Durham Central School District http://cns.cairodurham.org
