Re: blocking dialups
- Date: Tue, 13 Oct 1998 11:46:56 +0200
- Notice-requested-upon-delivery-to: unitfj@localhost
On Tue, Oct 13, 1998 at 09:44:42AM +0100, Clive D.W. Feather wrote:
> torben fjerdingstad said:
> > First, I think the ISP's should filter their dialups so they have
> > to relay through the local mail relay.
> Not this old chestnut again ?
Oh - old topic. I did not know that.
> If you bring this up on SPAMTOOLS-L, you will discover that there is a very
> diverse range of opinion on the topic. There are *lots* of legitimate uses
> for direct unrelayed mail.
Can you mention just one reason for not relay through the ISP's
mail server (except for sending spam)?
> > Until then, I would like to block all dialup/ppp ip's.
> > They are easy to find.
> Oh yes ?
Just look at the messages from mailer-daemon to find some dialup
spammers and do reverse lookups for the classe C network they
came from. I found a nice program for that at www.rootshell.com.
18.104.22.168 => guest1.linx.org
22.214.171.124 => guest2.linx.org
126.96.36.199 => guest3.linx.org
The hostnames usually clearly indicate if they are dialups.
Try to ping a few of them for verification. Or telnet
to the smtp port if really in doubt.
In your case I am in doubt because there are so few of them,
and I have not received any spam from them.
My problem remains to find out when a net used for dialups
is transferred to some other purpose.
Med venlig hilsen / Regards
Netdriftgruppen / Network Management Group
Tlf./Phone +45 35 87 89 41 Mail: UNI-C
Fax. +45 35 87 89 90 Bygning 304
E-mail: torben.fjerdingstad@localhost DK-2800 Lyngby