[c-nsp] policy routing by dest port?

[Mike]

Hi,

     I have a situation which may require me to reroute all dns traffic 
in my network comming from subscribers destined to offsite resolvers, 
over to one of my own resolvers instead. The subscribers are all 
terminated on 7201 and effectively I would like to have a rule I can 
drop in that says 'dns traffic to anywhere but my official resolvers is 
forwarded <here>'. The subscribers are mostly pppoe which means lots of 
virtual access interfaces on the router, and no adjusting the supplied 
dns servers via ppp won't do (I need to overcome corrupt / hijacked cpe 
which are ignoring these values).

Thanks for any pointers.

Mike-