I used to have this working but haven't been able to get it working again for a long time. I have two PCs behind a router at home. The Linux machine has an Oracle 8i instance and the W2K machine has 9i. When I try to connect to the Linux instance with SQL*Plus I get ORA-12535 TNA: operation timed out. I have tried all kinds of things in my tnsnames.ora and can't figure out why it's not working. Here's the info:

Linux machine localhost.localdomain
running Oracle 8.1.7
sid =ora1
ip=a number
Instance and listener is up and running

Windows 2000
has Oracle 9i and SQL*Plus running
tnsnames.ora entries for ora1

ora1 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 198.168.2.101)(PORT = 1521))
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = localhost.locldomain)
)
)

ora1 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 198.168.2.101)(PORT = 1521))
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = ora1)
)
)

ORA3 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 198.168.2.101)(PORT = 1521))
(CONNECT_DATA = (SID = ORA1))
)

Can someone help me or recomend a course of educating myself on this aspect of Oracle? I find this network stuff most confusing.