Hi,
If I try to run pcaspy in docker, I get the following error in CAS:
```
filename="../../../../src/cas/io/bsdSocket/casDGIntfIO.cc" line number=121
server isnt attached to a network - unable to continue
filename="../../../../src/cas/io/bsdSocket/caServerIO.cc" line number=116
Attempt to set server's IP address/port failed unable to attach explicit interface
filename="../../../../src/cas/generic/caServerI.cc" line number=59
server isnt attached to a network - CA server internals init unable to continue
terminate called after throwing an instance of 'int'
```
I understand that this has something to do with CAS's interface detection. However, if I run `softIOC` with the following db
```
echo "record(ai,"test_pv") {
field(VAL,"3")
}" > test.db
softIOC -d test.db
```
It works fine and I can `caget testpv` from another container without issue. This leads me to believe that the plumbing is there but that there is some assumption made in how CAS detects broadcast interfaces
that is not holding true in docker.
Have you all been able to successfully run pcaspy or cas-based servers in docker? Are there some environment variables I can set to help cas along?
I should note that setting `EPICS_CAS_INTF_ADDR_LIST="localhost"` WILL allow pcaspy will run in docker, but then the PVs are not visible outside that docker container, so it's not that useful.
Also for reference, here is what ifconfig returns from inside the container:
```
ifconfig
eth0 Link encap:Ethernet HWaddr 02:42:ac:11:00:02
inet addr:172.17.0.2 Bcast:0.0.0.0 Mask:255.255.0.0
inet6 addr: fe80::42:acff:fe11:2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:237 errors:0 dropped:0 overruns:0 frame:0
TX packets:186 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:240235 (234.6 KiB) TX bytes:11013 (10.7 KiB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:3 errors:0 dropped:0 overruns:0 frame:0
TX packets:3 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:208 (208.0 B) TX bytes:208 (208.0 B)
```
Thanks for the help,
John Sparger