question concerning traceroute?

Thu Oct 17 15:21:20 UTC 2002

> > > > > According to definition, is should take the same path, but are there any
> > > > > other cases that I should be aware of?
> > > > 
> > > > According to the definition, it is going to show you the path the packets
> > > > took from you to the destination, not from the destination back.
> > > > 
> > > 
> > > Unless you did "- g",
> > 
> > Not correct. -g specifies loose source routing on the way *there*, not back.
> 
> 	I think the intention was to indicate that you can
> traceroute -g <remote-router-before-host> <your-local-ip>
> 
> 	to get the path to and back.  -g requires an argument obviously.

That, obviously, is correct. 

	However, the remote ip in this case is your local IP, so you are
still getting a path to the destination.

	Even more importantly, LSR relies on every router on a forward path 
between <your-local-ip> and <remote-router-before-host> allowing LSR, which
is an invalid assumption.

Thanks,
Alex