Susan Day sent a missive on 2010-05-21:
Here are what the logs have to say:
@400000004bf6cfc4383bc65c delivery 6217: deferral: CNAME_lookup_failed_temporarily._(#4.4.3)/ @400000004bf6cfc4383c5eb4 status: local 0/10 remote 0/255 @400000004bf6d51e34d61d8c starting delivery 6218: msg 97881531 to remote suzieprogrammer@gmail.com @400000004bf6d51e34d6449c status: local 0/10 remote 1/255 @400000004bf6d51e37303e14 starting delivery 6219: msg 97881555 to remote suzieprogrammer@gmail.com @400000004bf6d51e373078ac status: local 0/10 remote 2/255 @400000004bf6d51e373143cc delivery 6218: deferral: CNAME_lookup_failed_temporarily._(#4.4.3)/ @400000004bf6d51e373241b4 status: local 0/10 remote 1/255 @400000004bf6d51e37807d0c delivery 6219: deferral: CNAME_lookup_failed_temporarily._(#4.4.3)/ @400000004bf6d51e3780bf74 status: local 0/10 remote 0/255
Extract from: http://nixforums.org/about25455-Help-Diagnosing-CNAME_lookup_failed_temporar ily.html
"The likely cause of this is qmail's inability to handle large DNS packets. The most-recommended solution is to install dnscache (from djbdns), which trims off some unnecessary data and usually makes these packets small enough for qmail to handle. The more correct solution is to apply the "oversize DNS packets" patch to qmail (see qmail.org). A hackish-but-fast solution is to choose one of Earthlink's MXs, and put it in your smtproutes file. Not good long-term, but it will get the mail out of your queue while you work on a better solution."
I wouldn't put earthlinks mx in your smtproutes but you could put in you isp's if you wanted to as a quick and dirty fix.
HTH
Simon.