Where can I find the output of exim's 'debug_print'?

Question

I'm trying to debug an exim configuration issue (Ubuntu) and I see lots of lines in the config such as:

remote_smtp:
   debug_print = "T: remote_smtp for $local_part@$domain"
   driver = smtp

However, I cannot figure out how to get the output of these statements. I've tried editing /etc/default/exim4 and adding various CLI parameters there such as -v, -d, -d+all and while they do have an effect, the debug_print lines are nowhere to be found (stderr,stdout,/var/log/exim4/mainlog).

How do enable and where do I then find the "T: remote_smtp for ..." output?

Answer 1

According to the exim docs

If this option is set and debugging is enabled (see `-d', `-v', and `debug_level'), 
then the string is expanded and included in the debugging output when the transport
is run.

You can verify this is working by running exim manually on the command line:

exim -d+all -bP transport remote_smtp

Did you try adding debug_level 1 to your exim config?

Answer 2

I, as well was not able to see any additional info by modifying /etc/default/exim4, and adding debug_level 1 in my configuration file was erroring out.

What worked for me was running exim4 in foreground using the same command line parameters that Debian/Ubuntu starts it with and adding d+all to it:

root@sh1:/srv/www/static# ps -A | grep exim
12886 ?        00:00:00 exim4
root@sh1:/srv/www/static# cat /proc/12886/cmdline
/usr/sbin/exim4-bd-q30m
root@sh1:/srv/www/static# service exim4 stop

Now start exim in foreground, note you have to add spaces between the parameters:

root@sh1:/srv/www/static# /usr/sbin/exim4 -bd -d+all -q30m
22:19:03 12969 Exim version 4.84 uid=0 gid=0 pid=12969 D=fffdffff
Berkeley DB: Berkeley DB 5.3.28: (September  9, 2013)
Support for: crypteq iconv() IPv6 PAM Perl Expand_dlfunc GnuTLS move_frozen_messages Content_Scanning DKIM Old_Demime PRDR OCSP
...