Hey Hey, ifconfig will work easily if you are behind a router or on a network of some sort. To set it up easier and make the changes static you can use netconfig (I believe for RH 7.3.. possibly just netconf tho.)
Check into what the others said about ifconfig... Also if perhaps your interfaces don't run correctly or something goes amiss...Try ifconfig -a (interface, eth0 ppp0 whatever) up.. This should load the device..
"Serenity is not the absence of conflict, but the ability to cope with it."