RE: SMTP authentication for broadband providers

First, a quick thanks to everyone that responded. I've received useful and excellent info from everyone.

We do not block on 25 outbound/inbound, but we are considering it for the residential broadband connections - maybe filter, proxy, or at least monitor it.

I should clarify one thing: We are considering REQUIRING SMTPAUTH for all connections from customers for relaying - whether they are on our IP space or not. I know this will only buy us a few months until the next round of viruses steal username/pass, but even then it will give us the ability to detect an infected/SPAMMING customer quicker and auto shut them down (vs having to shutdown the IP, and then the customer receives a new IP...)

My question is: Have any or many of the larger ISP's gone the route of REQUIRING all customers to use SMTPAUTH - regardless of where they are connected. Can anyone disclose who these regional or national providers are?

Thanks again

Well, over here we have gone that route, and we're a National ISP/NSP.

Customers can either A) Run their own mail servers, which makes them
responsible for the use (or abuse) of their own mail server, or,
B) If they choose to purchase mail services from us, we require
authentication (via SMTP_AUTH) to send/relay out.

Alexander Kiwerski
Senior Network Engineer
Winstar-IDT Network Operations & Security
Desk: +1 206 574 3121
Mobile: +1 206 571 0274