Your message was discarded by mailman, probably because it was html-only. Anyway:

On Wed, 2011-11-16 at 13:15 -0500, Mark Goldey wrote:

(gdb) p *auth_request->userdb->userdb->iface $2 = {name = 0x807023e "vpopmail", preinit = 0x8065d60 <vpopmail_preinit>, init = 0, deinit = 0, lookup = 0x8066010 <vpopmail_lookup>, iterate_init = 0, iterate_next = 0, iterate_deinit = 0}

OK, so "auth_request->userdb->userdb->iface->lookup" should call vpopmail_lookup(), it's not NULL as this says:

...

(gdb) bt full #0 0x00000000 in ?? ()

So something's going strangely wrong. Maybe gcc optimizations cause this and the real problem happens later. Try compiling auth process with optimizations:

• Remove -O2 from src/auth/Makefile
• cd src/auth ; make clean ; make ; make install

Is the backtrace different?