TroubleShooting
Updates and contributions welcome!
Suggested addition: walkthrough of how to go about debugging
You may like to add some of these to Exim command lines:
| Option | Description |
|---|---|
-v |
more verbose |
-d |
general debugging |
-d+all |
maximum debugging |
-d+all-memory |
max debugging less some tedious memory stuff |
-bV |
Always run this after making changes to the config file and before restarting Exim. It will check the syntax for you |
-bhc <ip_addr> |
fake smtp session as though you are at ip_addr. Use this to do a full test before committing changes |
This is very useful indeed, the "c" adds callout processing. If you don't use them then drop the c from the command line. You will have to be careful about how you use this to test all the cases you are interested in.
Suppose that my Exim box acts as a relay for my nasty expensive commercial internal mail system called "mail" and its address is 192.168.0.100. You make changes to the config file (say added callouts) but don't restart Exim yet - you need to check it out first.
Here I only show what you might type, there will be quite a lot of output from Exim about what it is doing.
# exim -bhc 192.168.0.100
helo mail
mail from:<user in my domain>
rcpt to:<random external address>
data
.
# exim -bhc <random external valid IP address>
helo <real name of above address>
mail from:<external user>
rcpt to:<valid internal user>
data
.
Having checked out the configuration you can then fairly confidently restart/reload Exim to put the new config into action.
# exim -bhc 1.1.1.1
If the ACL looks something like this, then you will get dropped early on:
acl_check_connect:
drop message = $sender_host_address is listed by $dnslist_domain
log_message = Remote host $sender_host_address is listed by $dnslist_domain ###002
dnslists = zen.spamhaus.org
See also the tools listed at ManagingExim.
-
http://www-uxsup.csx.cam.ac.uk/~fanf2/hermes/src/smtpc/
- written in C, supports STARTTLS, TLS on connect, AUTHs PLAIN and LOGIN, and PIPELINING. Relies on libraries usually installed on most modern operating environments, fulfilling the tool's primary goal of being able to be run on many systems "without requiring half of CPAN."
-
http://www.jetmore.org/john/code/swaks/
- written in perl. Basic functionality (sending a plain SMTP message) works with a standard perl install. Features include AUTHs PLAIN, LOGIN, CRAM-MD5, DIGEST-MD5, CRAM-SHA1, and SPA/MSN/NTLM; PIPELINING; DATA modifications including default data, default headers with custom body, and attaching files using MIME; ability to bind to a specific local interface for outgoing mail, ability to quit following specific parts of the SMTP transaction; STARTTLS and TLS on connect; option show timing delays on portions of transaction; ability to speak SMTP to a UNIX domain socket and a pipe (subprocess) in addition to internet domain sockets.
- telnet - telnet to port 25 and start experimenting.
- openssl - if you want to test a server at a fine level, as you would
with telnet, but want to use TLS, try the openssl client:
openssl s_client -connect SERVER:PORT -starttls smtp. Note the-starttlsoption is not supported in all version of the tool