Experimental Physics and
Industrial Control System

"Allison, Stephanie" <[email protected]> · Mon, 28 Apr 2008 10:04:10 -0700

Hello,

When multiple IOCs run on the same host, using the same EPICS_CA_SERVER_PORT, they use the same port for UDP channel connection requests but have to use different ports for the CA TCP connection (of course).  The CA reference manual says:

"If the CA server library detects that a server is attempting to start on the same port as an existing CA server then both servers will use the same UDP port, and the 2nd server will be allocated an ephemeral TCP port."

Is there a way to set the allowable range of TCP ports that the IOC is allowed to choose from for its TCP port?  In particular, on a RHEL4 linux server.

The reason for this is that we wish to have some of our CA clients, outside our firewall, connect directly to IOCs (both RTEMS and linux) inside the firewall.  We don't want them to go through a CA proxy gateway process and we don't want to have to set their EPICS_CA_ADDR_LISTs to include different EPICS_CA_SERVER_PORT values.  We also don't want to open up our firewall to all TCP ports just to allow this communication but are willing to allow a small range of predefined TCP ports.  And we don't want to combine our IOCs into one.  Essentially, we want each soft IOC to use the same EPICS_CA_SERVER_PORT for UDP connection requests but a predefined port for the TCP connection (ie, a new environment variable like EPICS_CA_SERVER_TCP_PORT which would be set differently in each of our soft IOC startup files).

Any thoughts?  Thank you,

Stephanie Allison

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System