I'm working in gentoo with qmail 1.03 and vpopmail 5.2.1. POP works just fine but authenticated STMP is a bust. Using some of the information I have found here and other places I used strace to try and find out what the problem is. As best as I can tell I am getting a bad file descripter when qmail is forking vchkpw.
For the gory details see http://forums.gentoo.org/viewtopic.php?p=490320 Can anyone point me in the right direction?