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How can I test my mail server without having remote access

I don’t have the luxury of having access to a useable computer from a site remote to my server, but I still need to test my email server, the TLS/SSL setup, smtp and smtpd.
There are some remote test sites that also want a valid email and password! But I’m a bit reluctant obviously.
I suspect my site is not quite right, but can’t find a way to test it, and to explain results of tests. Especially the TLS/SSL ones.
Does anyone know of any reliable testing options?

Robert

Comments

Re: How can I test my mail server without having remote access

By Andrey Repin at 12/03/2018 - 23:50

Greetings, Robert Chalmers!

What exactly you want to test?
I've got a good success using ssmtp with some wrappings.
Let me upload them… There: <a href="http://www.rootdir.org/upload/smtest.tar.xz" title="http://www.rootdir.org/upload/smtest.tar.xz">http://www.rootdir.org/upload/smtest.tar.xz</a>

Especially to test TLS, you can use openssl's s_client builtin.

It all really depends on WHAT EXACTLY you want to test.

Re: How can I test my mail server without having remote access

By Robert Chalmers at 12/04/2018 - 05:36

Thanks, that’s really interesting. I’m testing incoming mail, local mail and outgoing mail. Also mail if... I relay it via gmail.
The main thing I’m looking into is the ipv6 interactivity, along with ssl/tls and security.
An ipv6 only server is my goal, but I don’t know how achievable that is yet.

Re: How can I test my mail server without having remote access

By Wietse Venema at 12/03/2018 - 14:22

Robert Chalmers:
A crude hack is to give the machine an IP address alias, with the
IP address that you want to impersonate, then connect from the
machine itself to that address and port 25. That should work for
both plaintext and "openssl s_client".

BSD syntax: ifconfig em0 inet 1.2.3.4 netmask 255.255.255.255 alias
BSD syntax: ifconfig em0 inet 1.2.3.4 netmask 255.255.255.255 -alias
MacOS seems to support similar syntax.

At a higher level, Postfix XCLIENT allows you to pretend to have
any client IP address. <a href="http://www.postfix.org/XCLIENT_README.html" title="http://www.postfix.org/XCLIENT_README.html">http://www.postfix.org/XCLIENT_README.html</a>.
This is certainly sufficient for plaintext tests, but may require
some hackery for tests with "openssl s_client".

Wietse

Re: How can I test my mail server without having remote access

By Erwan David at 12/03/2018 - 14:11

Le 12/3/18 à 7:48 PM, Robert Chalmers a écrit :
Is tethering through a mobile phone an option ? That would give your own
laptop an external network conection (but you need to have a laptop and
a mobile phone plan allowing you to do this).