Brian,

Excellent suggestion. I have gotten so far away from code development that I clean forgot to even try the system debuggers. Largely because I am no longer familiar with their use, and the internals of Linux. However with your suggestion below I *did* give it a shot.

I 'straced' the courieresmtp process that was spinning on the message to be sent externally. Surprisingly it showed no activity in the trace. (?!? Uh-oh, a loop w/out a wait?) So I tried to attach to the parent courieresmtp process to see what was up there (and to see if the -f option would say anything about child process communications). In this case the process looked normal. It was sleeping on a select call:

select(5, [0 4], NULL, NULL, NULL

which made sense. The binaries are stripped, but I am not sure that that makes a difference to a strace. Have I missed something? The proc table shows that the process has two pipes open and two sockets open, but I'm not skilled enough to dig much deeper there. One socket is connected to the authdaemon at /var/spool/courier/authdaemon, but the other I have no info. on.

So, moving forward with Benjamin's advise, I decide to proceed with the recompile using "--without-ipv6". Sadly, however, that produced no change. Though moving through the thread to where I am now, it makes a lot of sense that this may in fact be the problem. I just can't figure out how.

Guys I *really* appreciate your help on this. I can't seem to figure it out on my own, and I'm really stumped. Thanks.

-Ace ps. I may not have mentioned - this is a Redhat system 7.3 w/ a 2.4.18-3 kernel, though I know of no problems with this release...