I seem to be having some issues backups various systems to a dedicated
Linux TSM server, which is behind a very secure firewall.

Eventhough both the TSM servers and all the clients are on the same
network, there seems to be some communications issues. I am seeing lots of
these:

6/19/2004 8:00:07 PM ANR8214E Session open with 25 failed due to
connection refusal.
6/19/2004 8:00:07 PM ANR0480W Session 3477 for node MUSTANG () terminated
- connection with client severed.
6/19/2004 8:00:08 PM ANR8214E Session open with 26 failed due to
connection refusal.
6/19/2004 8:00:08 PM ANR0480W Session 3478 for node DINGO () terminated -
connection with client severed.
6/19/2004 8:00:09 PM ANR8214E Session open with 27 failed due to
connection refusal.
6/19/2004 8:00:09 PM ANR0480W Session 3480 for node DOG () terminated -
connection with client severed.

The server TCPIP communications timeout is set to 3,600 and idletimeout is
set to 600.

Any good books/info/recommendations on dealing with this kind of
configuration ?

FWIW, most of the clients are Sun/Solaris systems.