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brent480's avatar
brent480
New Contributor
4 years ago

MB7420 modems keep rebooting during startup

Very similar to this, if not the same issue:

https://forums.cox.com/forum_home/internet_forum/f/internet-forum/28306/two-different-mb7420-modems-keep-rebooting-during-activation

The modem boots up fine and the internet connection is great. Logs show:


Time Not Established Critical (3) No Ranging Response received - T3 time-out;CM-MAC=00:40:36:5...
Time Not Established Critical (3) DHCP FAILED - Discover sent, no offer received;CM-MAC=00:40:...
Time Not Established Critical (3) No Ranging Response received - T3 time-out;CM-MAC=00:40:36:5...
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv4
Sat May 01 16:49:01 2021 Warning (5) DHCP WARNING - Non-critical field invalid in response ;CM-MA...
Sat May 01 16:49:01 2021 Warning (5) ToD request sent - No Response received;CM-MAC=00:40:36:5d:2...
Sat May 01 16:49:01 2021 Notice (6) TLV-11 - unrecognized OID;CM-MAC=00:40:36:5d:2c:60;CMTS-MAC=...
Sat May 01 16:49:48 2021 Notice (6) SW Download INIT - Via NMS

And then the modem reboots. Keeps doing it indefinitely.

It might have something to do with the client router dhcp or something because I can get it to stop doing the "SW Download INIT - Via NMS" if I reboot the router at the right time. Seems to have to pull a 192.168.100.x ip and then it does the external IP. Not sure why that works or maybe that has nothing to do with it. All I know is I have to reboot the router at the right time after the modem comes up, otherwise the "SW Download INIT - Via NMS" occurs and reboots w/ the same indefinite reboot cycle.


1 Reply

  • BenS1's avatar
    BenS1
    Former Moderator
    Hi @Brent480


    Sounds like you need some further troubleshooting on this issue. Please email us at cox.help@cox.com with your full name, full address.


    Ben S.
    Cox Support Forums Moderator