Re: Arp expire/timeout 2.1.132/2.2pre1

Florian Lohoff (flo@rfc822.org)
Mon, 4 Jan 1999 18:10:42 +0100

On Mon, Jan 04, 1999 at 07:13:56PM +0300, kuznet@ms2.inr.ac.ru wrote:
> Hello!
>
> > Thank god - no more ulrix on that box :) - Trying to netboot Linux/Mips
> > but the Prom seems to be mega-dumb ... Once it starts TFTP
> > it seems not to answer arp requests anymore :(
>
> Well, you could increase /proc/sys/net/ipv4/neigh/eth0/base_reachable_time
> from 30sec to something about twice longer, than tftp time
> and, probably, /proc/sys/net/ipv4/neigh/eth0/delay_first_probe_time
> to tftp time.
>
> What is not clear: 15sec should be enough to load image.

It is definitly not - tftp is 512 byte packets and with
a 1.4MB kernel and a slow decstation :)

> I have an impression, that this arp entry never enters to reachable
> state (i.e. server never receives arp reply) Could you make tcpdump?

It does - how would it then be able to BEGINN a tftp download.
It starts the tftp download and after some seconds it stops transferring.
I discovered the bug by doing a tcpdump - When the tftp stops
i can see the tftp server trying to do an arp request but
the client (Decstation prom) doesnt answer so the tftp times out.

Flo

-- 
Florian Lohoff		flo@rfc822.org		      	+49-5241-470566
Good, Fast, Cheap: Pick any two (you can't have all three).  (RFC 1925)


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