On 10 Aug 2006, at 19:12, Hank Nussbacher wrote:
I'll answer on-list since this answer can benefit others. The primary reason that the ISP wants to block outbound webmail spam is because the 100s of BLs on the Internet end up blocking large segments of the IP space due to spam reporting by end users. The spammer can end up "burning" quite a few IPs before the feedback loop of user->spam report->BL->ISP->block is completed. Therefore the ISP wants to be proactive and shut off the spam before it even starts. Even if it means losing revenue.
This seems to imply that you're using dynamic addressing. The rather obvious solution would seem to be that you provide static addressing. It also makes it rather easier to identify the spammer when the complaints come in since you won't need to grovel through your RADIUS logs.