Posted: Mon Sep 04, 2006 16:50 Post subject: Choosing new WAN MAC address resolves packet loss and DHCP?
I'm using a WRT54G v5 with DD-WRT v23 SP2 Micro and Comcast is my ISP. Yesterday I began to lose my Internet connection, where the only solution was to manually release and renew the DHCP lease from the router.
Wondering if there weren't other problems, I also pinged some Internet sites and noticed anywhere from 4-7% packet loss. I wanted to see if the issue was with my router, so I connected my cable modem directly to my PowerMac running OS X 10.4.7, and had 0% packet loss and no DHCP problems.
I tried a number of different things, including replacing the cat5 cable connecting my cable modem and router (it looked a little shabby), but that didn't work. What did resolve the issue was changing the WAN MAC address from DD-WRT Micro's default (00:40:10:10:00:02) to a MAC address I copied from an old D-Link router.
DD-WRT and the router had been performing fine for probably a month now. Any ideas why I all of a sudden had problems, and why changing my MAC address fixed it?
I think this is probably going to be because of a P2P related issue. If its anything like the situation I've got, the cable modem will give out a virtually static IP dependant on the MAC address. DD-WRT appears unable to handle in some regard the load generated by a large number of P2P connections. Changing the MAC of the router means that the IP assigned by the cable modem changes, & therefore DD-WRT doesn't get the P2P connections routed to the old IP.
(These connections are still made whether or not the P2P program is actually running; Your IP will probably have beem cached)
Could you explain to me how this would be P2P related in a little more detail?
I personally never use P2P apps except very rarely, but my neighbor who shares my connection does (Gnutella, from what I gather). However, when this occurred he had been gone for a few days and his computer shut off.
Since modifying the MAC address everything has been okay, so I won't change the settings in the meantime. I told him to quit using P2P if he wants to share my connection and also setup an access policy in DD-WRT blocking all P2P apps from his MAC address.
Problem should be solved.
I'm not sure why he'd want to use P2P anyway since no ports are forwarded to his PC; with BT he'd be getting pretty horrendous downstream speeds.
I think the original P2P analysis is probably accurate. I remember the day problems began to occur I would release and renew my DHCP lease and then watch the number of active IP connections rise into the low 100s, with nothing more attached than my PowerMac and Linux machine (which I examined for strange traffic and saw nothing).
Blocking P2P from my neighbor upstairs should hopefully be a good enough solution.
