Comcast DNS/POP performance question

[Robert La Ferla]

Resending because I used 'x' instead 'n' for the ips below and the 
mailing list software thought it was obscene content!  ;-)

Since Comcast uses a single hostname for their POP server, are they 
doing a DNS trick to route regional traffic to different IP addresses 
for multiple POP servers?  e.g.  Boston's pop.comcast.net resolves to 
nnn.nnn.nnn.1 and California's resolves to nnn.nnn.nnn.2, etc... Or are 
they really using a simple powerful POP server to handle all the traffic 
for comcast.net?  I ask this because if they are doing a DNS trick and 
you don't use their DNS servers, performance can suffer.  Anyone know 
the facts?