Subject: question??

From: Guangsheng Liu <[email-masked]>
Date: Wed, 05 May 1999 17:57:48 -0400

Hi, 
  Currently, we are trying to write a piece of code to find the default 
gateway on the LAN ( avoid the manual configuration for every PC ). 
  Does any body know if it is required for a router to support RFC 1256
"ICMP Router Discovery Messages"? 
  If that's true, that will be great. If not, some advice will be highly 
appreciated.
  
  Liu, Guangsheng

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From: Ari Ollikainen <[email-masked]>
Date: Wed, 05 May 1999 16:21:23 -0700

>   If that's true, that will be great. If not, some advice will be highly

From RFC1812, Requirements for IP Version 4 Routers:

4.3.3.10 Router Advertisement and Solicitations

   An IP router MUST support the router part of the ICMP Router
   Discovery Protocol [INTERNET:13] on all connected networks on which
   the router supports either IP multicast or IP broadcast addressing.
   The implementation MUST include all the configuration variables
   specified for routers, with the specified defaults.

   DISCUSSION
      Routers are not required to implement the host part of the ICMP
      Router Discovery Protocol, but might find it useful for operation
      while IP forwarding is disabled (i.e., when operating as a host).

   DISCUSSION We note that it is quite common for hosts to use RIP
      Version 1 as the router discovery protocol.  Such hosts listen to
      RIP traffic and use and use information extracted from that
      traffic to discover routers and to make decisions as to which
      router to use as a first-hop router for a given destination.
      While this behavior is discouraged, it is still common and
      implementors should be aware of it.

-- 
   OLTECO               Ari Ollikainen 
   P.O. BOX 3688        Networking Technology and Architecture  
   Stanford, CA         [email-masked]           
   94309-3688           415.517.3519

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From: Ari Ollikainen <[email-masked]>
Date: Wed, 05 May 1999 16:21:23 -0700

DISCUSSION