Re: [OT] RFC 822?
On Sat, 16 Nov 2002 10:45:09 -0500
"Edward Guldemond" <thedebategod@yifan.net> wrote:
> On Sat, Nov 16, 2002 at 02:48:53AM -0600, Gerald V. Livingston II
> wrote:
>
> > Many ISP's do not bounce mail sent to addresses that do not exist
> > because robot software can use that info to build a database of
> > valid addresses at that domain for spamming purposes.
>
> Doesn't this break RFC 822? I would think that a mail server should
> bounce mail for addresses that do not exist anyway for the reasons you
> mentioned. Oh well, that's what they get for running their mail
> machines on Windows NT/2000...
Yes, it breaks 822. But it's slowly becoming necessary for smaller
operations. I worked for a smal ISP a few years ago and saw one of these
robots in action. Through regular scanning of the logs we saw a LOT of
bounced messages. Reading through them the robot started with 2
characters and was working its way up. 00@isp.net, 01@isp.net, etc. We
blocked it by hand somewhere around bm7@isp.net. It was sucking the smtp
server rescources hard. About three weeks later every customer we had
with a valid address having 3 or fewer characters (lower than bm7)
started getting spam from multiple sources. Whoever used the robot just
compiled a list of the non-bounce addresses and sold the list.
Really nasty.
G
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