I have a dual-homed XP pro machine that I use to access two separate
networks. When accessing the Internet I generally prefer to use
Network "A" and its gateway. To set this preference I went into
Network Connections > Advanced menu > Advanced Settings... then made
sure my Network A adapter was at the top of the "Connections:" list.
This works fine except for times when I temporarily would like to use
Network B for Internet access. For example, at times I would like to
do basic troublshooting accross both networks with pings, tracert's
etc. Is there a way (without having to change the NIC priority as
above) to choose which nic gets used in a ping or tracert request? I
haven't seen an option like this before.

Also, is there a way to disable DNS on one NIC (e.g. for Network "B")?
If DNS on Network A goes down I'd like to know before my system
automatically reverts to using Network B.

Thanks.

Paul

Looks like you already know what to do but would like it to be
"nicer."

Well, TCP/IP is designed to seek new routes automatically, behind the
scenes when things go down. Now if you want to see what goes on
underneath, in a "nice" manner, you are entering the realm of
commercial, expensive, network tools.

I can't think of a PING-using-this-route utility but look, it may
exist. To me, since this is only used for troubleshooting, and doesn't
happend often, I personally wouldn't mind doing the temporary changes.
Rather than changing the the priority by the method u mentioned, I'd
use the ROUTE command, or simply physically unplugging the segment I
don't want.

As far as it telling u what failed, my employer has made us available
a usd$15,000 network monitoring workstation (HP Openview) that has a
map of the whole network with the different "pipes," If anything goes
down, that pipe turns to red. Pretty nifthy stuff.

El-chepo monitoring:

I suppose you can run a script that routinery pings the
next-hop-addresses and pops up a window when they fail.