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SubjectRe: /proc/net/arp

On Thu, 26 Dec 1996, A.N.Kuznetsov wrote:

> Try to enable "total" proxy arp:
> arp -s netmask "" dev eth0
> (excuse me for "wrong" syntax, I forgot how it is made in net-tools's arp:
> the idea is to set wildcard proxy entry on eth0)
> Now your router will answer to ALL arp requests,
> this nice facility exists since ~2.0.0.
> If you know, what prefixes should be proxied, you can limit the range:
> arp -s A.B.C.0 netmask "" dev eth0
> How it works. When router receives an arp request, it looks
> up its routing table, and if route goes via different interface
> and a matching entry in proxy arp table is found, it answers.
> Simple, smart and powerful. (I stole the idea from Cisco IOS 8-))

Thanks I'll try it. As usual, as soon as I write code to perform some
kind of service, it's OBSOLETE!!!!

> There is no other way to read it. I said "bad idea" not about
> reading /proc/net/arp, but on using arp cache for taking routing
> decisions.

Well I know that if there is host aaa.bbb.ccc.ddd in the arp cache at the
remote server, and it's got no way "out", it has got to be proxy-arp(ed)
and routed via my local PPP server. Seems to work fine. I play the "decnet"
trick of updating routing at about 2 second intervals. If the remote
host is shut down, the proxy-arp entries and the routing goes down in
4 seconds instead of waiting for the arp-cache to expire. This lets an
incomming mail server message, for instance, know that the host is not
reachable so it doesn't have a long timeout. It will try again later.

> > This IS the broadcast address.....
> >
> Thank you! I found this bug. You can apply this patch or
> just make something sort of:
> Alexey Kuznetsov.

Okay! I will apply the patch.

Dick Johnson
Richard B. Johnson
Project Engineer
Analogic Corporation
Voice : (508) 977-3000 ext. 3754
Fax : (508) 532-6097
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Penguin : Linux version 2.1.16 on an i586 machine (66.15 BogoMips).
Warning : It's hard to remain at the trailing edge of technology.

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