SWAKS is a general purpose testing tool for SMTP. For basic SMTP testing it’s a more convenient, scriptable alternative to running a transaction by hand, but it also lets you test things that are difficult to do manually, such as authentication or TLS encryption.
It’s a perl script that installs fairly easily on OS X or any Linux/unix system (and can be installed on Windows, if you have perl installed there).
It’s pretty well documented, but it can be a bit overwhelming to start with. Here are some simple recipes:
Send a test email:
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swaks -f you@example.net -t someone@example.com |
Check to see if a recipient exists:
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swaks -f you@example.net -t someone@example.com \ --quit-after RCPT |
Send via a particular server:
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swaks -f you@example.net -t someone@example.com \ --server mail.example.com |
Test user authentication for a smarthost:
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swaks -tls --server example.com -f you@example.com \ -t someone@example.net -ao --auth-user=you |
Test to see if a server supports opportunistic TLS:
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swaks -tls -s mail.example.com -f you@example.net \ --ehlo your.host.name --quit-after FROM |
(The backslashes are just there to split a single command line into two, so you can read it easily on this narrow blog).
SWAKS has a lot of other tricks too – adding headers, using specific protocols and ports, attaching content. It’s a very useful tool, and gets even more so when you add a little bit of shell scripting to automate your testing further.
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Don’t forget to run “swaks –support” to see which extra Perl modules you can install to round out the capabilities of swaks.
It’s in EPEL if you’re using RedHat/CentOS/etc.
Yes! It’ll run out of the box with minimal dependencies, but a lot of the more useful features (authentication and TLS especially) need those extra modules.
Swaks is awesome. I use it almost daily to run thru new policy testing.
Definitely, It’s always in Postmaster toolbox 🙂
This looks awesome. Thanks for the recommendation.