Experimental Physics and
Industrial Control System

Chip Watson <[email protected]> · Wed, 25 Aug 1999 09:08:39 -0400

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

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System