> ... > My understanding of why CNAMEs are prohibited for MX hosts is that they can > introduce loops. The last paragraph of Section 5.1 explains how a sender > should attempt to locate itself in the list of MXes, ordered by preference. > You may want to compare that paragraph with the historic discussion in RFC > 974, > which, under "Minor Special Issues", says:
The other issue: a sending server can resolve the CNAME and rewrite the address on you. I saw this years ago. E.g.: foo.com with a CNAME of “bar.com” foo.com with an MX of “some-good-mailserver.example.com” Sending email to “j...@foo.com” resulted in an email to “j...@bar.com” — the sending MUA / MTA resolved the cname on me. (I think it was qmail at the time.) -Jeff ------------------------------------------------------------------------------ New Year. New Location. New Benefits. New Data Center in Ashburn, VA. GigeNET is offering a free month of service with a new server in Ashburn. Choose from 2 high performing configs, both with 100TB of bandwidth. Higher redundancy.Lower latency.Increased capacity.Completely compliant. http://p.sf.net/sfu/gigenet _______________________________________________ courier-users mailing list courier-users@lists.sourceforge.net Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users
