Bug#297174: More research

[Andreas Bogk]

In fact, the problem only happens when libnss-ldap is using a TLS
connection for LDAP queries.  So this problem is related to GNU TLS
being used in two different places within the same address space.  It
might have to do with GNU TLS being initialized twice, or some other
problem with the global state of GNU TLS.

Also, the error message suggests that exim4 receives a TLS alers from
the other side of the connection (a thunderbird MUA in my case too).  It
is probably necessary to rig both sides of the connection with some
debugging, if looking at the globals of GNU TLS doesn't help.

Andreas