On Wed, 13 Mar 2002, Suresh Ramasubramanian wrote:
> +++ Phil Pennock [exim-users] <13/03/02 06:12 +0100>:
> > On 2002-03-13 at 10:39 +0800, Suresh Ramasubramanian wrote:
> > > Urgh. In postfix at least ...
> > Yet more postfix on the exim list? Sheesh Suresh, what happened to
> > Diplomacy? ;^)
>
> Heh - but it seems a pretty simple thing to do - and postfix has the right
> idea on how to handle it (checking for smtp banner being the same as your
> own)
Well, exim has the right idea - don't connect to its own IP addresses.
Perhaps it should automatically recognize '0.0.0.0' as being 'its own
address'.
>
> One place I can see this break is in a "security by obscurity setup" where
> several hosts banner with the same smtp banner. And by some weird means,
> send mail to each other. Or I could be wrong - never tested it out in such a
> situation.
>
> > > Your common or garden labrea tarpit.
> > I thought that labrea tarpits shrank the TCP window down to 0?
> > Oh wait, perhaps it did. Hrm, know of a telnet/netcat like utility
> > which can give me information about the window sizes? (I don't think
> > that I'm missing a weird telnet(1) escape).
>
> tcpdump, I'm afraid.
>
> > > Children / grandchildren of existing processes by any chance?
> > My cleaning was too thorough for me to now be able to tell. :^) "exim
> > -bpc" is now less than 200, it had climbed to quite a few thousand.
>
> Owch
>
> > Support will so *love* me in the morning, when they see how many
> > customers I've blocked from the smarthosts this night, and then some cgi
> > scripts chmod'd to 0 too! My little present to them. ;^)
>
> Lovely. The scent of fried luser in the morning ...
>
> --srs
>
>
> --
>
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>
>
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