postfix config with a strange option

[Maaz]

I have to configure a Mail Server.
SMTP server: Postfix
POP3 Server: qpopper

First
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for some users, we have to implement a very strange option... i.e those(35) users can send emails to anyone and anywhere, but they cant receive emails from out-side-world...they(35 users) can only receive emails from our own domain, but they cant receive email from out side.

Second
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please share/recommend a good/step-by-step opensource anti-spamming guide for postfix

Regards
Maaz

[Matti_Kurkela · Accepted solution]

For your first question, this seems to be exactly what you need:

http://postfix.wiki.xs4all.nl/index.php?title=Client_sender_recipient_restrictions

For your second question:

http://www.postfix.org/docs.html
See the part "UCE/Virus".

MK

[Maaz]

Thanks for the quick help.
I would also appreciate, if you also share your google "search string" ;)
actually I google a lot but didnt found the answer/solution of the first question...thats why I am asking you to also share the 'search string'

Regards
Maaz

[Matti_Kurkela]

No search string, because I did not use a search engine at all.

I have seen similar requirements in the past and guessed that your requirement was not so very strange after all... so I was certain quite a few people had already implemented something similar. So I estimated there was a good probability that this might be included in the Postfix FAQ or other similar document.

I just went to the website of Postfix's author: www.postfix.org. Then I clicked on "Howtos and FAQs" and started checking the Tables of Contents of various resources listed in there.

On the Main Page of the Postfix Wiki (3rd link on the Howtos and FAQs page) this caught my eye:

"policies to restrict users to send emails only to internal domains and receive and receive emails only to certain domains" - why, that's more or less exactly what was asked for!

This "human-powered search" took less than two minutes, so I don't consider it a lot of effort at all.

I already knew the URL of the Postfix website... but when looking for information on a well-known open-source software named "foo", a web address like "www.foo.org" would always be my first guess.

MK