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<== Date ==> <== Thread ==>

Subject: Re: network problem w/ ioc
From: "Dale L. Brewe" <brewe@pnc.aps.anl.gov>
To: Maren Purves <m.purves@jach.hawaii.edu>
Cc: Chip Watson <Chip.Watson@jlab.org>, tech-talk@aps.anl.gov
Date: Wed, 25 Aug 1999 15:03:06 -0500
It seems the routing is in fact getting screwed up in some way. What seems to work is to add "routeAdd" lines to the ioc startup w/ the most necessary workstations. This has been working for an hour or so thus far. Thanks for everyone's help.
Dale
At 01:14 PM 8/25/99 , Maren Purves wrote:
Dale,

yes, the routers could act differently depending on how they are/were
programmed. We don't use "routeAdd" as long as we stay on the same
subnet. I just looked up an old startup file where the ioc (temporarily,
we were still testing then) was on a different subnet than the devices
it was connected to, and in that case we used a routeAdd that had the
router's address and the subnet specified.
My understanding is that a routeAdd "0" , "x.x.x.x" tells the router
that all traffic is going "out" (and the programming of the router
decides whether "out" really means "out" or not).

Maren Purves


Dale L. Brewe wrote: > > Chip > Well, something along these lines seems plausible, I guess, altho the > gateway has not changed, nor have the ioc parameters. However, these > problems surfaced a few days after a new main switch/router was installed. > Clearly the problem seems to be at a pretty basic level, as I have troubles > pinging the ioc with no CA clients running. I haven't found anything that > looks bad in either hardware or software. In the ioc startup, I have > routeAdd "0", "x.x.x.x" for our subnet gateway. Is this correct? It worked > before, but could the routers be acting differently for some reason? > Dale > At 08:08 AM 8/25/99 , Chip Watson wrote: > >Dale, > > > >Your problem is similar to one I tracked down at PSI. If you > >have a gateway (default routing node) improperly set in the > >boot parameters of the IOC, then the following scenario can > >happen: > > > >(1) the first client connects, but the ioc sends all traffic for > >that client through the gateway > > > >(2) the gateway eventually sends a message to the ioc telling it > >what the correct ethernet address for that host is (it doesn't want > >to carry traffic unnecessarily) > > > >(3) the ioc mistakenly updates the gateway address instead of > >installing an explicit host entry > > > >(4) the second client connects, and the ioc attempts to route > >all traffic through the gateway again, but now it uses the > >"updated" address for the gateway, which is client one > > > >(5) client one refuses to forward the packets (lazy, huh?), so > >the ioc appears to drop off the net for everyone except the > >first client to have connected > > > >Log into the ioc via the console if you can, and you can watch > >this scenario play out. Then, check your boot parameters and > >either fix or remove the gateway entry. > > > >Chip

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dale L. Brewe PNC-CAT/U. of Washington ph: 630 252 0582 fax: 630 252 0580 Mail: Argonne National Laboratory/APS Bldg 435E sector 20 9700 S. Cass Ave. Argonne, IL 60439 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


References:
network problem w/ ioc Dale L. Brewe
Re: network problem w/ ioc Dale L. Brewe
Re: network problem w/ ioc Maren Purves

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