I have several static routes setup on my workstation. These routes are started at boot time. They are reliable because my network topology doesn't change often. If it does change, I know that I need to make modifications in the script.
Here's an example.
#vi /etc/rc3.d/S97static_routes
#!/usr/bin/sh
route add net 192.168.100.0 192.168.105.1 1
:wq! (quits and saves)
I just added the class C network 192.168.100.0 via the router 192.168.105.1. These IPs are only used for illustration purposes.
To manipulate the routing table
Route Add, Route Change, Route Delete, Route Monitor, Route Flush