I was at one of my in-laws neighbors homes the other day, he needed some help setting up Rabbit.TV and his Chromecast. I had never heard of Rabbit.TV, while it is cheap, $10 for the year, I found it very hokey and very difficult to navigate. Plus I believe it just links you to all the free content, but places it all in one convenient spot – I don’t know and not the point.

When I was all finished he asked if I wanted an extra cable modem he had. He had been mailed the modem in error or ended up not needing it after he bought it, I can’t remember which. I hesitated at first as I really need to stop collecting ewaste, but I took it and I am glad I did. I looked it up when I got home, nothing fancy just a Motorola SB6141. I was using a Ubee DDM3513 at the time. I originally has some Motorola Dinosaur but it had died, the Ubee is what was given to us in its stead. I haven’t had a lot of issues but I do feel it was sluggish at time. Not evidence to back it up thats just the overall feeling I was given from The Family. They two modems are both DOCSIS 3.0 the difference is (that would make a difference) that the SB6141 can handle “channel bonding of up to eight downstream channels and four upstream channels” (up to 300 Mbps downstream, 100 Mbps upstream). The Ubee is 4/4 (up to 171Mbps downstream, 122Mbps upstream). I Googled the hell out of the Motorola for a few hours and I came up with a lot of posts and forum comments on the performance. Most people advertised they were getting a higher Mbps with the SB6141 than other modems for their current speed tier (hitting 12Mbps on a 6Mbps account for example). So I decided to swap the modems out.

It actually went very smoothly, on Comcast’s side. I connected the new modem (SB6141) in place of the Ubee and plugged my netbook directly into it. It connected to the net within about 3 minutes or so. When I transferred the modem to the server/router is when I hit a snag. My ClearOS box wouldn’t grab a new IP address from the modem. If I watched it closely I could see it get the local 192.168.100.10 address, then drop it, then switch to the ISP public and then drop it 10 seconds later. Then I got to stare at the spinning loading logo forever. The netbook would grab it no problem every time. I power cycled the modem and the server/router many times, made no difference. I even tried cloning the MAC of the netbook on the server/router, it did take the clone but it made no difference either. What worked for me was to delete the ethernet card under “IP settings”. Mine is eth11 so I just deleted eth11 and then added it back in again. Voila it worked.

Speed tests ran from speedtest.net and speakeasy both report 12Mbps down, 1Mbps up. Prior to the modem switch I was only hitting 6.5Mbps, which is my speed tier cap. So 12Mbps on a 6Mbps speed tier – score, at least for now.

Update 10-22-2015: I have come to find an easier solution (other than not using Comcast and therefor not needing a cable modem). If you SSH into the box you can simply release and renew the IP of the ethernet port.

sudo dhclient -r your_nic followed by
sudo dhclient your_nic

For example my card is enp3s0 so I would type:

sudo dhclient -r enp3s0

That should release and renew the IP for you. I found this out after upgrading to ClearOS 7. The old trick of deleting and re-adding the NIC wasn’t working anymore. So it appears that it is not just Comcast and their cable modems, ClearOS has something to do with it.