LXer: Tip of the Trade: Sendmail's Greet_Pause
 

Published at LXer:

Slamming is a popular spammer tactic in which the spammer quickly fires off SMTP messages without waiting for responses from the receiving server. A poorly behaved MTA will then accept traffic from the spammer, instead of rejecting it as it should. But even well-behaved MTAs are affected because of the sheer volume of traffic with which they are forced to deal. The venerable sendmail, as of version 8.13, has a nifty feature called "greet_pause" that not only rejects incorrect SMTP transactions, but also discourages re-sends.

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