I have seen this error when TSM is not completely up and running - for example, 
after you halt it and then bring it backup.  

Can you start a dsmadmc session with the server? If not, wait a few minutes and 
try it again.  
Can you start dsmadmc from another node?  If so, then a TCP/IP problem exists 
on the node.
Is the dsm.opt file pointed to the correct TSM server?  If you are using a 
fully qualified hostname in the opt file, is the hostname resolvable?
Is the TSM server pingable?  Perhaps, the TCP/IP stack on the server is out of 
resources.

Mahesh

>>> Larry_Clark AT THRUWAY.STATE.NY DOT US 01/23/02 11:01AM >>>
Hi:
Just installed a new client.
It can ping the server and the server can ping the client. However, on invoking 
a backup i get:

tsm> back /home/root/*
Node Name: EIMSX
ANS1017E Session rejected: TCP/IP connection failure

Selective Backup function invoked.

ANS1017E Session rejected: TCP/IP connection failure

from dsmerror.log

01/23/02   11:02:07 TcpOpen: TCP/IP error connecting to server.
01/23/02   11:02:07 sessOpen: Failure in communications open call. rc: -50
01/23/02   11:02:07 ANS1017E Session rejected: TCP/IP connection failure

Any suggestions?