nanog mailing list archives
Re: Despamming wholesale dialup
From: Phil Howard <phil () whistler intur net>
Date: Fri, 30 Oct 1998 12:38:41 -0600 (CST)
Bryan Bradsby wrote:
Block port 25 (only) from all "open modem banks" (TM) to my SMTP servers. If implemented on a large enough scale, the modem user will be 'encouraged' to use the SMTP server supplied with their account. Make each dialup customer go through, and be authenticated by their own SMTP server.
I think I see an additional problem creeping in here. The question is whether a dialup user should use the SMTP server of the facility provider, or of the ISP that actually resells the account. You could have virtual ISP resellers with no facilities at all, but lets take a look at a small ISP that does have facilities, and is reselling dialup to a national provider so his local business customers can have roaming access without calling an 800 number. If the small ISP opens their SMTP server to the IP addresses of the big national dialup provider, which they would have to do in order to be able to handle that roaming customer who could be just about anywhere, will they not also be opening themselves up to being a relay for any spammer that uses any reseller of that national provider? Will not such spammers then have access to every ISP doing reselling via that national one? I think the SMTP server that should be used when dialing that national provider is the SMTP server provided by that national provider, unless some kind of VPN is used (to be more technically correct, use the SMTP server of the provider of IP addressing). Roeland's issue still applies when the dialup customer is using his domain name as the FROM/REPLY. But if the national provider SMTP servers accept any domain name in the FROM/REPLY, and just log the reality as it sees it in the header (e.g. dialup port and time which can be cross checked with the access logs), then anyone can use these dialups, and spammers won't get an advantage of being able to spew their filth to other than the SMTP server of the dialup provider. -- -- *-----------------------------* Phil Howard KA9WGN * -- -- | Inturnet, Inc. | Director of Internet Services | -- -- | Business Internet Solutions | eng at intur.net | -- -- *-----------------------------* philh at intur.net * --
Current thread:
- Re: Despamming wholesale dialup, (continued)
- Re: Despamming wholesale dialup Greg A. Woods (Oct 29)
- RE: Despamming wholesale dialup Sean Wade (Oct 29)
- Re: Despamming wholesale dialup Scott Gifford (Oct 29)
- Re: Despamming wholesale dialup Bryan Bradsby (Oct 29)
- Re: Despamming wholesale dialup Phil Howard (Oct 30)
- Re: Despamming wholesale dialup Bryan Bradsby (Oct 30)
- Re: Despamming wholesale dialup Henry Linneweh (Oct 30)
- Re: Despamming wholesale dialup scott w (Oct 30)
- Re: Despamming wholesale dialup Tim Pozar (Oct 30)
- Re: Despamming wholesale dialup Phil Howard (Oct 30)
- Re: Despamming wholesale dialup Bryan Bradsby (Oct 29)
- Re: Despamming wholesale dialup Phil Howard (Oct 30)
- Re: Despamming wholesale dialup Lyndon Nerenberg (Oct 30)
- Re: Despamming wholesale dialup Phil Howard (Oct 30)
- Re: Despamming wholesale dialup Derek Balling (Oct 30)
- Re: Despamming wholesale dialup J.D. Falk (Oct 30)
- Re: Despamming wholesale dialup Ray Everett-Church (Oct 30)
- Re: Despamming wholesale dialup Dalvenjah FoxFire (Oct 30)
- Re: Despamming wholesale dialup Steven J. Sobol (Oct 30)