Is there a way to reduce the lease time of the WAN IP address in DD-WRT? It seems like this should be an easy setting to find, but I'm not seeing it anywhere in the settings.
WAN lease time is controlled by your ISP not your router. DD-WRT won't have a configuration for it. I haven't seen a DHCP server that allows the client to specify lease time.
Manually releasing the lease and renewing may not get you a new IP address. The server usually has a database of the addresses assigned, and will try to reassign the same address.
Some ISPs will rotate addresses over time to discourage people from running servers. Trying to forcibly change the IP address frequently may attract unwanted attention to your activities.
I've read of articles where a DDWRT router was behind an ATT 3801HGV Gateway and if the DDWRT router was in a DMZ zone on the 3801HGV that DMZ zone would automatically be issued a 10 minute lease time. You can log into the 3801HGV and change the DHCP lease time from the default 24 hours to whatever you want but it will not change anything in the DMZ zone.
I've also read if you enter the code below on the DDWRT router in - Administration then Commands then click Save Firewall:
After entering the code above it was supposed to force the DDWRT router to renew the WAN IP address after 5 minutes. You can check the status of this by clicking on the Status tab, then WAN, then watch the connection Up time and remaining lease time. The remaining lease time should not get below 5 minutes, or so they say.
I must be doing something wrong because my lease time still counts down from 10 to 0 and renews which causes anything downloaded past 10 minutes to freeze! Really annoying. Any other suggestions?