Experimental Physics and
Industrial Control System

"Mark Rivers" <[email protected]> · Tue, 17 May 2011 06:11:15 -0500

Are you sure that there is not  firewall (e.g. iptables) running on that machine?

Mark

________________________________

From: [email protected] on behalf of Bruce Hill
Sent: Tue 5/17/2011 12:12 AM
To: Techtalk
Subject: Channel Access not connecting

I've been having trouble with one linux machine where my IOC's appear
to be running correctly, dbgf works from iocsh, but caget from another
window on the same machine fails to connect.     I suspect it has something
to do with how the multiple interfaces on this machine are configured, but
so far have been unable to find a solution.

# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:1E:68:79:5C:4E
          inet addr:134.79.32.161  Bcast:134.79.35.255  Mask:255.255.252.0
          inet6 addr: fe80::21e:68ff:fe79:5c4e/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:190759 errors:0 dropped:0 overruns:0 frame:0
          TX packets:43567 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:18427912 (17.5 MiB)  TX bytes:9772031 (9.3 MiB)
          Interrupt:19

eth2      Link encap:Ethernet  HWaddr 00:1E:68:79:5C:50
          inet addr:192.168.254.2  Bcast:192.168.254.255  Mask:255.255.255.0
          inet6 addr: fe80::21e:68ff:fe79:5c50/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1238443 errors:0 dropped:0 overruns:0 frame:0
          TX packets:879202 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:80539799 (76.8 MiB)  TX bytes:64420869 (61.4 MiB)
          Interrupt:20 Base address:0x4000

Gateway is 134.79.35.1

I'm running with defaults for the EPICS_CA* and EPICS_CAS* env variables,
but have also played with EPICS_CA_ADDR_LIST, EPICS_CA_AUTO_ADDR_LIST,
and EPICS_CA_INTF_ADDR_LIST with no success.

See attached files for casr, epicsEnvShow, ifconfig, and netstat output
for more configuration details.     We're running base 3.14.9
everywhere, but this
is the only machine showing this problem.

The casr output includes:
UDP Server:
UDP 0.0.0.0:0(): User="", V4.0, 0 Channels, Priority=0

This looks wrong to me, as my working IOC's show a valid UDP addr, but I'm
not sure how to fix this, or even if this is the root problem.

Any suggestions would be appreciated.
Thanks,
- Bruce

P.S.  When I run caget, tcpdump shows:
# /usr/sbin/tcpdump -i eth0  -n -nn udp dst portrange 5064-5065
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
21:46:55.934345 IP 192.168.254.2.54260 > 134.79.35.255.5065: UDP, length 16
21:46:57.179960 IP 134.79.32.161.43268 > 134.79.35.255.5064: UDP, length 48
21:46:57.211939 IP 134.79.32.161.43268 > 134.79.35.255.5064: UDP, length 48
21:46:57.275932 IP 134.79.32.161.43268 > 134.79.35.255.5064: UDP, length 48
21:46:57.403935 IP 134.79.32.161.43268 > 134.79.35.255.5064: UDP, length 48

--
Bruce Hill
Member Technical Staff
SLAC National Accelerator Lab
2575 Sand Hill Road M/S 10
Menlo Park, CA  94025

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System