Re: blocking dialups
- Date: Tue, 13 Oct 1998 14:19:17 +0100
torben fjerdingstad said:
>> 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)?
(1) You are then reliant on the ISP's mail server; if that breaks in any
way, you're dead in the water.
(2) A closed user group can authenticate mail to addresses based on the
sender address; for example, I can email certain internal lists from my
dialup, but not everyone else can.
(0) I buy access to the *Internet* from my ISP, not access to their
>>> 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.
> Sample output:
> 18.104.22.168 => guest1.linx.org
> 22.214.171.124 => guest2.linx.org
> 126.96.36.199 => guest3.linx.org
Which proves what ?
> 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.
And what did you get for the above three ?
Clive D.W. Feather | Email: clive@localhost | Tel: +44 1733 705000
Regulation Officer | Home: clive@localhost | or: +44 973 377646
London Internet Exchange | | Fax: +44 1733 353929