[Greylist-users] Database performance

Ken Raeburn raeburn at raeburn.org
Thu Jan 5 08:16:15 PST 2006

On Jan 5, 2006, at 02:05, Brian Ross wrote:
> We're running the db_maintenance script regularly, expiring  
> approximately 1.25 million rows on a nightly basis with the  
> maintenace taking approximately 1.5 hours.


Have you got other front-line defenses set up that might lighten the  
load on the greylist database?  For example:

  - check SMTP "HELO" command for a system claiming its hostname is  
your MX server's own IP address (i.e., connect to and send  
"HELO"); at various times I've found 20-40% of my spam fits  
that category, but no legitimate mailer will do this, though I'm told  
some old, crufty PC mailers will send their own IP addresses instead  
of their hostnames

  - delay sending greeting banner a little while, SMTP spec says the  
client has to wait but some malware just connects and spews HELO etc

These should have no risk of losing legitimate mail (at least, with a  
short enough delay on the latter), but both checks can happen before  
you get far enough into the session for greylisting to have anything  
to put into its database.  And then there are blacklists, which  
aren't quite so risk-free...

If you're not doing stuff like these already, they might help lighten  
your load a bit.  If your numbers are with the extra hurdles already  
installed, see "yow" comment above. :-)


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