Elliott,
EPICS parameters (such as EPICS_CA_ADDR_LIST) have an upper limit on their
length of 80 characters. Additional characters are truncated. This limit goes
away with EPICS version 3.13, at which time I believe EPICS will no longer
impose any limit.
The IP addresses specified in EPICS_CA_ADDR_LIST can be subnet masks. For
example, the mask that would allow a process to connect to any of the
accelerator control system IOCs is 129.57.239.255. Using masks can be
problematic, however, because frequently networks are configured to not permit
broadcasts through the network. For example, the accelerator control system
hub allows broadcasts into the control system (from outside) only from a list
of specified IP addresses. Broadcasts from other addresses are blocked by the
hub. When a specific IP address is listed in EPICS_CA_ADDR_LIST, however, a
broadcast is not used. This means that CA clients that want to talk to (a few)
specific IOCs can get through the control system hub.
Matt