I think I see something funny going on. It looks as though your Linux host is listening on
eth1:
NCP>tell 2.17 show exec
Node Volatile Summary as of 1-NOV-2009 13:05:01
Executor node = 2.16 (SKETTI)
Circuit = eth0
State = on
Identification = DECnet for Linux V2.6.31-14-generic on x86_64
2.16 shouldn't have answered for your Alpha system.
--Marc