Greg A. Woods wrote:
> So long as you implement error response rate limiting -- i.e. don't feed
> them the last line of the error response for at least 60 seconds or so,
> then they can't "pound away", and certainly not several times a minute,
> but rather will be restricted to making leisurely retries that don't
> impact the performance of your other SMTP clients.
We only do single line error responses - and teergrubing can be a bigger
drag on your system than it can be on random other systems.
Keeping a connection open for that much time, for multiple borken MTAs,
is painful.
Such behavior (even after we 5xx or REJECT at RCPT TO) just earns the
offending IP a nullroute at our end. Problem solved, for us at least.
Might even automate this sort of thing, setting up temporary nullroutes.
srs
