Rephrase my previois post: why mustsaslserver not behaving as it should be

Question

Shane,
I think it is better to rephrase my question:
In a previous answer you said the following:
An email server/client was able to connect to your server on port 25
You can enforce SASL on port 25 connections from non-local hosts (not defined in INTERNAL_IP) by modifying the imta.cnf configuration file and changing the tcp_local channel definition. Replace the "maysaslserver" keyword with "mustsaslserver".
But I've just found this on my testing server:
After changing the maysaslserver to mustsaslserver for the tcp_local
stanza,
PC clients CANNOT connect to my testing server (for mail relaying)
, which is correct.
But mails from email servers
^^^^^^^^
CAN, becos incoming mails are still able to come in and sent to
the local users.
The mapping file is okay as the stanza is :
INTERNAL_IP
$(ip.of.this.host/24) $Y
127.0.0.1 $Y
* $N
Why?

Answer 1

Okay, Shane.
Let me describe what I've tried on this JSMS server.
But before I do so, here is the relevant lines in my mappings file:
INTERNAL_IP
$(158.182.1.76/24) $Y
127.0.0.1 $Y
* $N
My line in imta.cnf , i.e. before I've changed it looks like:
! tcp_local
tcp_local smtp mx single_sys remotehost inner switchchannel identnonenumeric sub
dirs 20 maxjobs 7 pool SMTP_POOL maytlsserver maysaslserver saslswitchchannel t
cp_auth missingrecipientpolicy 0 loopcheck
When I tested it by sending mail to one of its users from outside, the mail was received
okay. This is expected.
Now according to the manual, if I change the "maysaslserver" in the line above
to "mustsaslserver", then if I did the same test mentioned above,
it will reject the mail because it won't accept any smtp connection from
anything other than its own IP (158.182.1.76) or 127.0.0.1
Is my understanding CORRECT ?
But when I did the same test (i.e. sending mail to it like I've described above,
there's no difference. In other words. it did not reject the mail but received it)
Why?