North American Network Operators Group|
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RE: Providers removing blocks on port 135?
On Fri, 19 Sep 2003, Matthew Kaufman wrote: > > I agree entirely with this. You shouldn't call yourself an ISP unless you > can transport the whole Internet, including those "bad Microsoft ports", > between the world and your customers. I disagree. In my opinion a NSP shouldn't filter traffic unless one of its customers requests it. However I strongly believe that an ISP (where it's customers are Joe Blow average citizen and Susy Homemaker) should take every reasonable step to protect it's users from malicious traffic and that includes filtering ports. For example I have no reservation about NATing basic dialup users. I also have no problem with filtering ports for services they shouldn't be running on a dialup connection (HTTP, FTP, DNS) or for services that IMHO have no business on the public internet (including every single Microsoft port I can identify). To not do so is IMHO to run a network in an extremely negligent manner. We do this very thing with email. We filter known malicious messages, attachments, and spam from email. I don't think there's a reasonable person among us that can complain about that. Why not do it to network traffic then? If we should allow every bit of traffic to pass unmolested by ACLs then we should allow all email to pass by unmolested by anti-virus and spam checks. It's a two-way street. > On the other hand, what's a provider to do when their access hardware can't > deal with a pathological set of flows or arp entries? There isn't a good > business case to forklift out your DSLAMs and every customer's matching CPE > when a couple of ACLs will fix the problem. For that matter, there isn't a > very good business case for transporting Nachi's ICMP floods across an > international backbone network when you can do a bit of rate-limiting and > cut your pipe requirements by 10-20%. A good point. Justin