Proxy arp should only replay on specified interface.

[Gleb Smirnoff]

  Iasen,

On Fri, Oct 07, 2005 at 05:58:55PM +0300, Iasen Kostov wrote:
I> 	IMHO proxy arp should only replay on specified interface not on every
I> arp capable interface which recieved request for the proxied address.
I> If lets say host A have arp capable if0 and if1 interfaces and U set:
I> 	route add -host 1.0.0.2 -iface if1 -proxy
I> 
I> and then a request is recieved on if0 for 1.0.0.2, host A will replay
I> that it has it (which IMHO is wrong as the proxy route is set for if1).
I> 
I> 	This sometimes is a big problem for our PPPoE/VPN server when the
I> client uses linux or some small routers (e.g Linksys or something)
I> probably linux based. It happen that sometimes (when the link is down or
I> god knows why) it broadcasts arp "who-has" and the gateway replays. Then
I> this host try to use ethernet path and not the (right) tunnel path until
I> arp cache expires (which is not real fun as there is firewall rules
I> blocking ethernet path :)).
I> 
I> 	And even worse :) - I can think of ways to bypass routing protocols
I> using proxy-arp routes like the one mentioned above. But it will not
I> work if proxy-arp behaves the way it does now.
I> 	And 1 thing more - there could be a switch which restores (or turns on)
I> old behavior.
I> 
I> (patch agains 5.4-STABLE is attached)

Isn't this what you need?

http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netinet/if_ether.c?rev=1.140&content-type=text/x-cvsweb-markup

-- 
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