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Troubleshooting NIC problems-
Possible device drivers are le0, hme0, eri0 (used by SunBlade 150s), and others.

ifconfig -a, will show existing network interfaces. If there is nothing shown except for the loopback interface then you'll need to ifconfig eri0 plumb.

the /etc/hosts file should only list <tab> localhost (check final hosts file tomorrow)
in /etc/inet/netmasks the file should list (<your IP range with a 0 for the last octet) <tab>

now "ifconfig eri0 inet (exact IP) netmask (is the subnet supposed to go here?) + broadcast + up"
in /etc there should be a hostname.eri0 with just the hostname listed in it, if not check for just hostname. if there is one and it's correct then mv hostname. hostname.eri0

there should not be a file called .unconfigured in /etc

the much easier way is to clean up the hosts and netmasks files and then do a sys-unconfig