Alan Hannan alan at
Sun Aug 4 02:42:35 UTC 1996


  Could you use loopback interfaces to do what you want?


  ps i'm not really a fan of ip unn, I think /30 serial networks
     should be considered responsible allocation by most all parties.

  pps i'm really a big fan of loopback interfaces for the purposes
      of monitoring a router as a node, as opposed to the plurality's
      idea of an interface having a cpu

.........  Avi Freedman is rumored to have said:
] > The biggest problem with using non-routable ip addresses on numbered interfaces
] > whether point to point or frame or atm or whatever, is that you lose outside
] > connectivity from those interfaces.  We tried this, but the essential
] > traceroutes from our core routes are too important when debugging BGP 
] > problems to the outside.
] > 
] > Robert Bowman
] > Exodus Communications Inc.
] Exactly.  Especially when you have downstream customers who only announce
] routes via BGP to you and/or other providers, it can be important for them
] to be able to trace out with a source address that has global connectivity.
] We usually use unnumbered interfaces, though, for singly-connected customers
] (unless their routers can't support unnumbered interfaces).  The only
] major gotcha with that is that if they're using a Real Router (that deleted
] routes associated with interfaces that aren't available), you can't
] get to their router if their ethernet is down...
] Avi

More information about the NANOG mailing list