Autoconfiguring level 2 visibility between subnets in a shared network?

Simon Hobson dhcp1 at
Thu Jul 27 20:33:35 UTC 2006

John Hascall wrote:

>Typically this is something that your router and the routing
>agents on the clients would handle.  192.168.22.client would
>send a packet destined for 192.168.33.other to 192.168.22.router
>and in addition to forwarding the packet the router can send
>a ICMP redirect back to 192.168.22.client telling it that it
>can talk directly to 192.168.33.other -- so only the first
>packet makes the extra hop.

Something I was going to add - but ...

.. recently I was setting up a network with two routers and found 
that at least one of the Windows machines did NOT respond to a 
redirect (filtered as a security mechanism perhaps ?) I've also never 
looked into whether the process also works on a shared network - I am 
familiar with "you can route to X via Y", is there an equivalent ICMP 
redirect that says "you can route to X via your local interface" ?


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