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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Despamming wholesale dialup
> 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? How about checking the MAIL FROM: part of the message? If a spammer tries to use an invalid address, the small isp's sendmail can reject it outright. > 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). Yes, but how does the user know to change this? A redirection (some policy routing and port fudging will help,) but it may be easier for the visp client to be authenticated in some way, (like a radius scheme that picks up the current remote ip address of the user and allows relay from that address while the user is online.) TERRY
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