[j-nsp] Bypass-routing traceroutes

Marco Marletta marco.marletta at garr.it
Thu Dec 11 14:29:47 EST 2003

> > How can I perform traceroutes from my Juniper through AS X towards all
> > destinations I receive on this eBGP peering, instead of using the best
> > routes coming from inside?
> You cannot prefer the eBGP routes locally on the router and not
> re-advertise to iBGP neighbours?

Too difficult.. i have some more eBGP peers.. distinguish eBGP routes by
neighbor.. i needed a quick-hack ;-)

> > I want to test the AS X capability of reaching some destinations without
> > using it for traffic...
> Or a quick hack prefer a couple of hosts (random /32 in what ever
> interesting prefix reachable via your new peer) via a static route
> pointing at your new peer.

Yep! That's a quicker hack :-)

> > N.B.
> > traceroute <desired destination> source y.y.y.y gateway y.y.y.y-1
> > bypass-routing
> > appears not to work...
> luser at router> traceroute bypass-routing interface so-1/2/2
> Works for me - until I managed to crash the M160 5 sec. later ;)

I don't have such an option on my JunOS [by chance.. so I cannot crash my
M20 .. :-))) ]

traceroute <desired destination> bypass-routing ?
Possible completions:
  <[Enter]>            Execute this command
  gateway              Gateway to route through
  inet                 Force traceroute to IPv4 destination
  inet6                Force traceroute to IPv6 destination
  no-resolve           Don't attempt to print addresses symbolically
  routing-instance     Routing instance for traceroute attempt
  source               Source address to use in outgoing traceroute packets
  tos                  IP type-of-service field (IPv4) (0..255)
  ttl                  IP time-to-live value (or IPv6 maximum hop-limit
  vpn-interface        VPN interface for traceroute attempt (IPv4)
  wait                 Time to wait for a response (seconds)
  |                    Pipe through a command



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