Choosing new WAN MAC address resolves packet loss and DHCP?

Discussion in 'DD-WRT Firmware' started by bedouin, Sep 4, 2006.

  1. bedouin

    bedouin LI Guru Member

    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?
  2. Guyfromhe

    Guyfromhe Network Guru Member

    That MAC you posted is not a Linksys mac, is that the MAC listed on the bottom of your router?

    It's possible that was somone elses MAC address and it was causing some kind of weird layer 2 issue... And could have easily confused the DHCP server and the cable modem...

    Check that MAC, thats probably the problem.
  3. bedouin

    bedouin LI Guru Member

    Yeah, the MAC is not a Linksys MAC -- it's what DD-WRT Micro changes the router's default address to. It's very likely that someone else running DD-WRT Micro had the same address, especially in a heavily populated area like mine.

    Your suggestion popped into my head, while someone else in the DD-WRT forums suggested my neighbor who shares my connection could be to blame, since he occasionally uses some P2P apps. Basically, even with his machine shut off, some machines could have still been hitting my IP address.

    At any rate, I set a policy in DD-WRT disabling all p2p access for his machine and asked him not to use those apps anymore (I rarely do myself) and changed the MAC address to a unique one.
  4. Guyfromhe

    Guyfromhe Network Guru Member

    Good to hear it's working :)
    Your problem doesn't sound like a P2P issue, and the incomming connections after the fact wouldn't be enought to influence it anyway and would stop within a couple minutes...
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