MailScanner & CentOS5/Sendmail

Greg Matthews gmatt at nerc.ac.uk
Fri May 16 12:08:24 IST 2008


David Lee wrote:
> Another method available is sendmail's 'virtusertable' which gives:
>    user at foo.com -> id-A at machine-Z
>    user at bar.com -> id-B at machine-Y
>    a.n.other at baz.org -> id-C at machineX
> 
> And (the bit you probably want to know) if the recipient is not in the
> left-hand-side of the table then the email is rejected at SMTP stage.
> (There are many other details, but this MailScanner-list discussion is
> already approaching "off-topic"!)
> 
> This 'virtusertable' facility can be useful at large sites with multiple
> domains. Our two main domains each have around 25,000 entries.
> 
> So we use:
>  o  'virtusertable': accept email for known users, reject unknown users
>     (with frequent, automated updates from Personnel (HR) databases);
>  o  'access': occasional blocking of external things that are bothering
>     us (updates relatively infrequent; done by Postmaster).

additionally, we also make use of milter-ahead as we cannot always be 
authoritative for users at domains which we relay for. Using this milter 
allows us to delegate that authority to the domains themselves

> 
> 


-- 
Greg Matthews           01491 692445
Head of UNIX/Linux, iTSS Wallingford

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