[Sussex] Securing Mail Servers

[Jon Fautley]

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John Crowhurst wrote:
> On Sun, April 16, 2006 17:01, paul.morriss at tokenbay.co.uk said:
> 
>>We have added security that it will be bounced if the from address is not
>>valid but is there a way so that only authorised users can send mail..
>>
>>Apologies if this has been asked many times but I am new to mail systems.
> 
> 
> Look at SMTP-AUTH, so only authorised (via a password or secure
> interchange) will be able to send email.
> 
> Exim:
> http://www.debian-administration.org/articles/280
> 
> Sendmail:
> http://www.sendmail.org/~ca/email/auth.html
> 
> Postfix:
> http://postfix.state-of-mind.de/patrick.koetter/smtpauth/

SMTP auth is what you're after.

I'm a bit concerned that you've managed to create an open relay box.
Most decent mailservers make this extremely hard.

Please, please, please be careful, and TEST your mailserver before you
release it to the wild. If you've got an open relay, apart from annoying
a large percentage of the Internet population, you're a) likely to make
your company look bad if they start sending spam, b) get your server
blacklisted from most of the world, and c) you're likely to get your
internet connection terminated, or at least shut down with little/no notice.

Check out the open relay scanner at abuse.net - I don't remember the
full URL, but it should be googlable or on the main abuse.net site.

Cheers,

/j
- --
Jon Fautley RHCE, RHCX <jfautley at redhat.com>   direct: +44 1483 739615
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