I have installed RHEL 5 on my dell laptop.but my network card which is of Broadcom Netlink(TM) Fast ethernet is not detected.

The output of command /sbin/lspci | grep -i net is:
09:00.0 Ethernet controller: Broadcom Corporation Unknown device 1713 (rev 02)

0c:00.0 Network controller: Broadcom Corporation Dell Wireless 1390 WLAN Mini-PCI Card (rev 01)

could anyone help me out
Thanks

See what modules are already loaded using "lsmod". Its unusual for RedHat not to have some sort of driver that will support this card.

You could try downloading and compiling a driver from source if it's available on BroadCom's website. You could try loading in some generic drivers which may work with your BroadCom NetLink card...

For example, most BroadCom cards I've experienced are NetXtreme varieties which use either bcm5700 or bnx2 drivers (bnx2 being third party and not included as part of the OS). A default driver which may work is tg3.

So you could try...

modprobe bcm5700
modprobe tg3

Try setting up the NIC after doing that, edit the config under /etc/sysconfig/network-scripts/ifcfg-eth0 (or whatever eth it is) then see if it works and is so with which of the drivers.

Once you've found the driver it works with add this to /etc/modprobe.conf like this for example...

alias eth0 bcm5700

Then rebuild your ramdisk

cd /boot
mkinitrd -v -f initrd-`uname -r`.img `uname -r`

Reboot. Voila! You might want to make a backup of your initrd image BEFORE you recreate it though.