I've been experiencing a problem where DHCP is having issues sporadically and only some or all of the devices on my network become "Limited", have no "IP address", "cannot automatically get an IP address," assign multiple devices the same IP, or disconnect some devices at random times. It seems like there becomes an issue where IP addresses are not properly assigned or able completely unable to be assigned.
I am using a SMC Networks SMCD3G. Whenever this issue happens, I have two options to solve it:
1) Unplug the Comcast modem box completely for a coupe of seconds and then
2) Go to 10.1.10.1 and change the LAN DHCP lease time to anything besides what it currently is (example: 1 to 2 days or 2 days to 1 week), wait a few minutes and then try reconnecting.
This happens with the Ruckus APs (with DHCP disabled so that the Comcast modem assigns all IPs to devices as 10.1.10.x where 10 <= x <= 199) that are set up around the building, and the various AirPorts and other low-class routers that some people use throughout the building for their own personal use (many of which create their own 192.168.x.x addresses). I've even tried just using an Ethernet connection between my computer and the modem directly, and the issue occurs with that as well, so I know that it is not any of the routers or APs that I have.
I have already called the support number because I thought that there could be something wrong with the modem itself, but they said that they could not figure out the issue since it was not occurring at the time that I called...
I have already tried the "Connection Troubleshooting Tips" thread. Are there any other solutions? This issue has become more frequent (multiple times a week) and is very inconvenient.
Solved! Go to Solution.
Is anyone from Comcast going to assist with this issue? I see that you've replied to other topics made after mine.
For the past three days, the Internet has gone down at exactly 11:07pm without fail, and then I have unplug the entire modem for some seconds and then plug it back in.
It sounds like the best course of action here would be to swap the modem out for another one. Though, you could also try do a hard reset on the modem in the hopes it downloads some updated firmware which may fix the issue.
Before swapping the modem try replacing the power adapter/wall wart. The SMC is generally very reliable with IPv4. The wall warts, not so much.
If you don't have one laying around that meets the specifications, you'd be better off just swapping the modem, which comes with a new one. You should be able to go into your local Comcast store and get it swapped out fairly quickly.
the wall wart must have the same polarity, the same connector, the same voltage. It can have a higher current that is OK but lower current is not OK. Be careful since some of the round power connectors have a smaller inside hole and other power connectors have a larger inside hole and if your inside hole is too large it won't make contact or the contact will be unreliable.
If you swap out the modem DO NOT REUSE THE OLD POWER WALL WART!!! It may be behind a bunch of junk and be a pain to pull out BUT SWAP IT. And, DO NOT RETURN the "broken" modem until you have verified the new modem works.
There have been cases where people have picked up a replacement cable modem that was same make a model and discovered the new hardware box was bad - so they put the old "bad" box back and magically it started working fine - because they didn't swap back the new power adapter and the old power adapter was bad.