How to check for existing mail accounts?

[Brian McKerr]

----- "Kevin Miller" <Kevin_Miller at ci.juneau.ak.us> wrote:

> Johnny Stork wrote:
> > its sendmail
> > 
> > Kevin Miller wrote:
> >> Johnny Stork wrote:
> >> 
> >>> I have noticed a large increase in the amount of spam coming in
> to
> >>> MS (latest) running on CentOS 5 and many are coming into
> >>> non-existent email accounts. Is there a check that can be done
> for
> >>> the existence of an account first, and then if non-existent,
> block
> >>> even before any scanning is done, let alone processing through
> MS.
> >>> 
> >>> Thanks for any suggestions that anyone can give
> >>> 
> >> 
> >> What MTA are you using?  You can run recipeint verification on
> >> sendmail via milters, and I'm sure Postfix has similar
> >> functionality... 
> >> 
> >> ...Kevin
> 
> Then see http://smfs.sourceforge.net/smf-sav.html
> 
> Note that this does both sender and recipient address verification. 
> I
> presume your gateway is forwarding on to another host where the
> recipients actually reside.  The milter uses ldap calls to get the
> recipient data, so your internal email server will need to be able to
> do
> that.  Ours is Exchange, which does.
> 

I have a Zimbra server which, of course, runs openldap and I *used* to do dynamic LDAP look ups to see if user accounts were valid from my MS/Postfix gateway. It worked well, but I have since changed to *not* use LDAP dynamically because whenever I do maintenance on the zimbra box, the gateway box cannot validate users and therefor bounces mail. Not good. I now have a script that runs every hour and it does an LDAP lookup and dumps all valid user account names into a file that then gets hashed for postfix to look up. Now I can leave the zimbra machine (vm) down for any amount of time during the night to take a 'cold' backup of it, without worrying about bouncing emails.

Cheers,


Brian.

 

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