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Re: [tlug] can't post to Mandrake expert.

On Sat, 30 Mar 2002 01:39:49 +0900, Gavin <> wrote to

> what is smarthosting?

An e-mail can be relayed by your MTA in either of 2 manners.

1) Your MTA can look up the MX for the recipient's domain, contact it
directly on port 25, and forward the e-mail that way. The trouble with this
method is that it is frequently used by spammers so that their ISP can't
detect the fact that they're sending out thousands of e-mails and shut down
their account on the spot. Many ISP's know of this practice and their MX
will more often than not refuse connections from known dialup pools, thus
stopping these spammers in their tracks.

2) The smart and netiquette-friendly way of doing things is getting your MTA
to forward all outbound e-mail to your ISP's SMTP server. It shows that
you're making no attempt at covering your tracks, and it's no longer going
to be your MTA trying to contact the recipient's MX, but your ISP, which
means that your mail *should* get through (unless your ISP is blacklisted
and the recipient checks RDBL databases). This is what "smarthosting" is.

The trouble with 2) is that some braindead idiots leave their port 25 open
not only to their own LAN but to the entire world. Spammers have
portscanners which detect this open port and subsequently use the idiot's
IP# as an SMTP server. The idiot's machine accepts the inbound spam and does
what it's told to do: forward it to the idiot's ISP for delivery to the end

Other ISP's begin to realise that the idiot's ISP is regularly used for this
purpose and blacklist its output relays. My own ISP,, is probably
the world champion for this with anything up to 8 output relays blacklisted
at any given moment.

Anyway, I hope this answers your question.

| G. Stewart   -- |
| Port de Pontille, FR-37500 CHINON, FRANCE. |

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