Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Fri, 14 Sep 2012 16:58:34 -0500

Hi Ralph,

On 2012-09-14 Ralph Lange wrote:
> On 14.09.2012 22:38, Mark Rivers wrote:
> > If we want to be able to access the soft IOCs from the wireless as well,
> > is the following sufficient:
> >
> > - Set each soft IOC to use a specific EPICS_CA_SERVER_PORT
> > - Open those ports in the firewall
> 
> That should work.

... except that you also have to add the server's IP with all of those ports 
to the EPICS_CA_ADDR_LIST settings of of all your wireless clients, which 
doesn't make it easy to add a new soft IOC.

> Two other options that might be preferable:
> - Run a CA Gateway on a (dedicated, maybe virtual) machine inside your
> beamline net, set it to a non-standard port, and open the firewall just
> for access to that machine/port. That way you do not need to set
> EPICS_CA_ADDR_LIST for all your other IOCs inside the beamline network
> (to have them see all the non-standard soft IOCs).
> - Run a CA Nameserver for all soft IOCs, and point your outside clients
> to the Nameserver. Answers to name resolution requests contain IP number
> and port, making all soft IOCs visible.

If you can arrange for a CA gateway or name-server to expose its server side 
as a IP address on your wireless subnet then you wouldn't have to configure 
anything for your wireless clients to be able to see any of your IOC PVs.

If you use a CA gateway then you can close the firewall ports including 5064 
and 5064, but you're then limited by the performance of the gateway.  If you 
need performance and don't mind firewall holes then a CA name-server is 
probably the best way to go.  It can be set up learn all your IOC's PV names 
automatically, so configuring it doesn't have to be complicated, although 
first-time searches of a new PV do take a tiny bit longer in that case.

Talk to Janet on Monday if you want help, she maintains the name-server.

- Andrew
-- 
Never interrupt your enemy when he is making a mistake.
-- Napoleon Bonaparte

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System