Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Thu, 31 Aug 2006 17:11:48 -0500

David Dudley wrote:

After a quick revision, I'm closer to operation.  I can now get the
data through the net from the NetBSD machine to the Linux machine if
I do "EPICS_CA_ADDR_LIST=10.145.5.38 ./camonitor fred".
I can start the example program or the excas program on the NetBSD
machine, and do "EPICS_CA_ADDR_LIST=10.145.5.38 ./StripTool" on the
Linux machine and see the data now.   It's getting better!  Is it
normal to have to specify the addresses in a list like that, or will
the problem go away when I move the NetBSD machine inside our
firewall?

If your machines are on the same subnet with the same subnetmask and
without a firewall they should connect up without your having to set
EPICS_CA_ADDR_LIST. By default Channel Access uses both TCP and UDP
traffic on ports 5064 and 5065, so if you have a firewall between them
you need to open up those ports. However that won't be sufficient if
you start running multiple CA servers on the machine inside the firewall
(at that point you'll have to turn off the firewall because the second
server will bind to a random TCP socket number).
It is possible to use CA across subnets, but you have to understand how
it works and configure things properly - see the Channel Access
reference manual for all the details if/when you need to do that.
I have a version of StripTool, alh, medm, and probe that all seem to
work OK on the NetBSD machine, but right now I can't access data on
the Linux machine because the NetBSD machine is currently connected
outside the firewall that protects the Linux machine.  I'll move the
NetBSD machine inside the firewall tomorrow and do more testing.

It sounds like the firewall is the source of your problem at this point.
- Andrew
--
There is considerable overlap between the intelligence of the smartest
bears and the dumbest tourists -- Yosemite National Park Ranger

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System