I have a WRT54G at home but I don’t use its routing capabilities, only wireless and LAN. There are only 5 ports on the device and one is dedicated as the WAN port. I want to turn the WAN port into a LAN port so I can make use of all 5 ports. How do you do it? As long as you have shell access (obtained by telnet on custom firmwares like dd-wrt or openwrt), just type in these commands:

For WRT-54G

nvram set vlan0ports="0 1 2 3 4 5*"
nvram set vlan1ports="5"
nvram commit


For WRT-610N:

nvram set vlan1ports="0 1 2 3 4 8*"
nvram set vlan2ports="8"
nvram commit


Then reboot the router. What we’re doing is assigning the (former) WAN port (0) to the LAN vlan, instead of the WAN vlan.