Re: IRX not responding to all packets.

John G. Thompson (jgt10@livingston.com)
Sun, 10 Nov 1996 19:20:20 -0800 (PST)

On Sun, 10 Nov 1996, Arnaud Girsch wrote:
> >> . R1 proxy ARP for 'C' hosts and has a default route to IRX and a /26 to R2
> >
> > Proxy ARP for 'C' hosts??? sounds like R1 and R2 are bridging 'C' into
> > the 'B' network. If R1 and R2 are routers, then I don't understand why
> > R1 is doing proxy arp for 'C'. It might help if you gave the actual IP
> > addresses.
>
> Hum .. R1 is not exactly bridging. It's routing IP, but proxying for 'C' /26
> addresses.
> R2 is only routing, no proxy.
>
> Again .. R1 is proxying b/c 'C' is a /26 inside 'B' which is /24.
>
> > > . R2 has a default route to R1, and a /26 to 'C'
> > Is 'C' a subnet of 'B'?
>
> Yes.
> Don't tell me to subnet 'B', I have some equipments that won't work without
> being in a /24 :-) ... and I don't want to assign a whole /24 to 'C' which is
> small.
> (If you have another solution than using another /24 or subnetting 'B', I'll
> take it :-) )
>
> > > >From any host on 'C', I can have TCP, UDP, antyhing to 'A', 'B' hosts.
> > > >From any host on 'C', I can ping the IRX, and even telnet to it.
> > > But ... from any host on 'C', I can't traceroute to the IRX. The UDP packets
> > > are sent correctly, but I got no answer.
> > > I can traceroute any host on 'A', I will have answers for all routers except
> > > from the IRX ("* * *" display)
...
> > > Any explication for that ? The IRX doesn't like proxy ARPs ? well .. it can
> > > connect from a 'C' host ...
> >
> > The IRX doesn't 'know' about proxy arps. You can do a 'sho arp ether0'
> > to see the arp table for the ether0 port and network interface. For the
> > IPs from 'C' you should see the same MAC address as the router R1 (which
> > I would guess is an Ascend pipline or an Adtrans ISDN box of some sort).
>
> Yes it does show the R1 MAC address, as it should.
> R1 is an Ascend Max as you guessed.

AH! Yes, I am VERY familiar with this situation. I helped setup some
parts of an ISDN dialin netowrk with an Ascend MAX 4000. The MAX is
bridging across the links to the dialup sites. You can confirm this by
looking at the radius or answer profiles, they will use the MAC address
of the connecting box.

> > If the above is really causing you some problems call in and open a case
> > so that someone can take a good look at your situation.
>
> Well ... as at that time I only had Win95 boxes on 'C'.
> Now the conclusion is that it was the Win95 "problem" reported and explained
> by Megazone few days ago on that list. It works ok with anything else than
> M$ traceroute.
> Anyone (Megazone ?) knows what's so different in their implementation ?

JGT

--
John G. Thompson      Livingston Enterprises Inc.    Phone: (800) 458-9966
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