It sure seems like this is a good demo of the best practice of having customers on their own VLANs with their own subnets. We have been doing this since we started offering colo services, is this less common than I thought?
John
That�s a very good question... I was also under the assumption that most providers would have adopted new practices rather then simply dumping customers on a single subnet/vlan... unless were going back in time 
As far as the "special daemon program" goes.. any packet sniffer will reveal all needed information to jack an ip.
I'm actually surprised that its taken spammers this long to figure out and utilize such vulnerabilities in networks... seeing how spamming is a multi billion $ industry...
few ways to limit ip jackings... keep your subnets small as possible, force the use of private vlans, as a provider... you should provide a way for your clients to be able to view their traffic patterns... in case of a hijack, they would notice the increased traffic and could bring it to the providers attention sooner then later... monitor your switch ports (snmp?) for bursts of outbound traffic (bandwidth / pps)...
-- Payam Chychi
John van Oppen wrote:
Date: Tue, 13 Jun 2006 21:35:14 -0700
From: John van Oppen
It sure seems like this is a good demo of the best practice of
having customers on their own VLANs with their own subnets. We
have been doing this since we started offering colo services, is
We actually go so far as to isolate certain services on their own
subnet/VLAN.
this less common than I thought?
I'm afraid so. I've worked on a good many networks where everything is
in one VLAN; a common argument for the practice is IP assignment
granularity. Rarely do I find MAC ACLs in place at the switch. (I'm
actually trying to remember a specific installation that had MAC
filtering set up by a prior engineer... I'm _sure_ I've encountered at
least a couple.)
Note that these observations are for small- and mid-sized networks.
Maybe things are better in the larger networks. YMMV.
Eddy