OT: Wiki - Postfix SMTP recipient verification

TCIS List Acct listacct at tulsaconnect.com
Mon Nov 20 17:05:14 GMT 2006

Steve Freegard wrote:
> Hi Postfixers,
> I've just added a how-to to the MailScanner Wiki to do the Sendmail 
> 'milter-ahead' SMTP recipient verification equivalent in native Postfix 
> which is far easier than building recipient maps for mail systems that 
> can reject unknown users at the SMTP stage.
> See 
> http://wiki.mailscanner.info/doku.php?id=documentation:configuration:mta:postfix:how_to:reject_non_existent_users#using_smtp_recipient_verification 
> for the info.
> I'm surprised you Postfixers didn't beat me to it - so now you've got a 
> Sendmailer editing your Wiki entries ;-)
> Cheers,
> Steve.

FWIW, we are doing this with exim now via ACLs, in the acl_check_rcpt (near the 

   deny message = user unknown
         domains = +route_to_domains
         !verify = recipient/callout=10s,defer_ok

(+route_to_domains is a SQL lookup that checks to see if the domain is one that 
we route mail to a "hidden" mailhub for, and one that we don't do other type of 
RCPT checks for, such as LDAP)

We then have a router set up that pulls the IP of the mailhub, and the callout 
uses that to do the verify against..


Mike Bacher / listacct at tulsaconnect.com
TCIS - TulsaConnect Internet Services

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