[c-nsp] Fighting Spam and IP Blacklists as an ISP

[Felix Nkansah]

Hi,

I know a big network service provider (mobile, fixed lines, DSL, leased
lines) whose entire IP block and ASN has been blacklisted.

They blame it on their subscribers, and they are looking for an effective
solution to the problem.

The spam firewall solutions I know (like Barracuda, IronPort) seem to be
effective at protecting enterprise mail servers configured to operate in the
backend.

I like to know of an effective solution for blocking transiting spam
originating from downstream subscribers, in the ISP network.

Which solutions, products, and techniques have you found to be effective.

Thanks. Felix