At 06:23 PM 10/28/98 -0500, Harold Willison wrote:
Greetings,
Let me explain the situation and see if I can get anyone to tell me how they are handling it.
We are offering wholesale dialup ports. When a user connects he is authenticated and can do whatever it is he/she wants to do on the net. Unfortuantely some have decided that they will relay spam off of other servers.
This is a problem.
To address this i have proposed installing filters that will only allow
these
folks to connect to port 25 of the ISP that has bought the ports. This way they are not able to relay off of anyone elses machine
The problem is for companies like ours that live by selling mail acounts to users of other ISPs. They need POP and SMTP access to our mail servers, from whereever they are calling. We are running sendmail v8.9.1 with all the anti-relay stuff and RBL besides. The problem you have is the same one we have for secured SMTP, maybe easier. How do you tell the site is secure? In this case testing for open relays is well known. What I really suggest, and this takes some work on your part, is to contact the site's admin and inform them of their open-relay status. If they won't close the relay, block them. Alternatively, you can assume that if they haven't gotten their relays closed by now they are too clue-less to do so and block them immediately, with notification.
that is using port 25 and the buyer of the ports should have the correct measures set up to prevent bulk mail from going out.
Will this be sufficient, providing that the server they are allowed to connect to has set up his mail server to prevent massmailing..?
Suggestions/comments? *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* | Harold Willison AGIS Network Engineering | * Senior Network Engineer 313-730-5151 * | noc@agis.net 313-730-1130 x-5649 | | harold@agis.net 24 hours a day, 7 days a week | | <http://www.agis.net>http://www.agis.net | \*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
___________________________________________________ Roeland M.J. Meyer, ISOC (InterNIC RM993) e-mail: <mailto:rmeyer@mhsc.com>rmeyer@mhsc.com Internet phone: hawk.mhsc.com Personal web pages: <http://www.mhsc.com/~rmeyer>www.mhsc.com/~rmeyer Company web-site: <http://www.mhsc.com/>www.mhsc.com/ ___________________________________________ I bet the human brain is a kludge. -- Marvin Minsky