Greylisting (WAS: gif attachments)

Matt Hampton matt at
Wed Aug 23 22:46:02 IST 2006

>>>> Try implementing greylisting on your servers. This has helped a lot with
>>>> this problem on my systems.
>>>> Even if you set the greylisting delay as low as 5 minutes.
>>> My big fear w/ Greylisting is that a (legitmate) SMTP server somewhere won't respect the "try again later" code, and instead just fail to deliver the mail.  I've heard rumours that some of the larger webmail providers exhibit this behaviour.
>>> Comments?

I ran it for about 6 months and didn't have any issues with it.  However
I then turned on sendmail's "greet_pause" facility and this caught
almost as much as grey-listing.

I decided to turn off the grey-listing as this was just another thing to
maintain and debug if someone complained.


More information about the MailScanner mailing list