Stealth Blocking

Eric A. Hall ehall at
Thu May 24 18:09:52 UTC 2001

> Remember that the spammer is handing the "open" relay one piece of
> mail with zillions of RCPT TO:s - rate limiting the outbound just
> means that the zillions of recipients sit in *your* queue that much
> longer.

I will add "further punishes/diminishes the harm of open relays" to the
"pro" column. ;)

> I have heard from multiple sources that the spammers are well clued
> enough to utilize multiple relays in parallel - if you rate limit to
> 1/N of bandwidth, they just use N relays at the same time.

If the rate limit is applied to *:25, then the *MORE* relays the spammer
uses, the longer it takes for him to do it.

Eric A. Hall                              
Internet Core Protocols

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