If your switch supports dhcp snooping, you can configure the port that connects to your dhcp server as trusted port and all other ports as untrusted (usually also your trunk ports should be configured as trusted, however for this situation it' should not be necessary). Then enable debugging of ip dhcp snooping events / packets (cisco specific command) and you should be able to see which port your rogue DHCP server is connected to (as well as its IP address IIRC).
Regards -- Markus On Feb 10, 2010, at 5:45 PM, Mark Tinka wrote: > On Wednesday 10 February 2010 03:31:26 am Okello Baldwin > wrote: > >> Iif you have some managed switches and routers on this >> network, just cross check the ip name-server command has >> got the right DNS ip address. Possibly these switches or >> routers have a different DNS ip assigned as the ip >> name-server. You could start by disabling the command >> using *no ip name-server* in global config mode. > > This has no bearing on transit traffic, only one traffic > being generated by the router. > > Moreover, while routers can be used as DHCP servers, there > is an abstraction between their internal DNS resolvers and > those they can assign via DHCP. > > Cheers, > > Mark. > _______________________________________________ > LUG mailing list > [email protected] > http://kym.net/mailman/listinfo/lug > %LUG is generously hosted by INFOCOM http://www.infocom.co.ug/ > > The above comments and data are owned by whoever posted them (including > attachments if any). The List's Host is not responsible for them in any way. > --------------------------------------- >
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