Solved: exim4 smarthost error A TLS packet with unexpected length was received

Only started in the last 2-3 days, exim stops delivering mail to smarthost. Logs have error: "A TLS packet with unexpected length was received"

Same symptoms on two servers delivering mail to smarthost. Ubuntu 12.04 LTS.

Simple solution:

Create file "00_localmacros" in /etc/exim4/conf.d/main

Insert the following two lines into the above file:

gnutls_compat_mode=true
gnutls_require_protocols=NORMAL:%COMPAT:-VERS-TLS1.1:-VERS-TLS1.2

As root, run dpkg-reconfigure exim4-config
(you don't need to change anything)

Then it just works.

More info: for me, both servers were using mail.iinet.net.au as smarthosts, but from the info on the web, it seems wider than iinet.