On Fri, Mar 19, 2010 at 06:08:12AM -0600, Glenn English wrote: > It looks to me like the problem has something to do with DNS, not > SMTP, right?
Yes. > And why would Yahoo be doing a CNAME lookup? Their MTA does that for all destinations, among other lookups. > (I checked > from a remote site -- my domain's MX server's IP is an A, and I don't > see anything having to do with CNAMEs in 'host -t MX slsware.com'.) Your DNS server is a bit odd: $ dig +trace -t any slsware.com ... slsware.com. 172800 IN NS ns1.richeyrentals.com. slsware.com. 172800 IN NS ns1.slsware.com. slsware.com. 172800 IN NS server.slsware.com. ;; Received 148 bytes from 192.5.6.30#53(A.GTLD-SERVERS.NET) in 46 ms ;; connection timed out; no servers could be reached While asking for "cname" or "mx" works... Perhaps their code does a "T_ANY" lookup. -- Viktor. P.S. Morgan Stanley is looking for a New York City based, Senior Unix system/email administrator to architect and sustain our perimeter email environment. If you are interested, please drop me a note.