On Wed, 13 Jan 1999, Adam D. McKenna wrote: > @ IN TXT "qmtp" > I know this has been suggested before. I was wondering what was wrong with > it.. IIRC, something about latency due to additional DNS lookups eating whatever benefit QMTP would have provided in the first place. DJB has documented a way to abuse MX preference values to indicate that QMTP should be tried first when connecting to a given MX. Since MX'es need to be looked up anyway, it's only apparent cost (ignoring than the inherent ugliness of abusing MX preferences in this way) seems to be the potential occasional QMTP connection attempt to sites that happen to use certain high MX preferences, but don't run QMTP server, and employ easily-spooked firewall administrators. ftp://koobera.math.uic.edu/www/proto/mxps.txt According to qmail/future.html, a "future version of qmail-remote" will support this (or some similar) mechanism.
