Home Lab question regarding ISP's equipment

jboogie81

Hey all,

Long time lurker, new poster here. So, i would like to configure one of my Cisco 1721's for home use to replace my ISP (Comcast) router (Motorola SMCD3GNV), but after configuring the router i remembered that when i moved and got new equipment, i can no longer just bypass Comcast's router like i used to. My old ISP setup was coax to ethernet modem, THEN separate router that i could pull out, but now Comcast distributes this SMCD3GNV to customers all-in-one device that from what i can tell does not allow you to bypass its routing capabilities. My question is what has anyone done to get around this? I can't be the only person with a cable connection straight to a non passable router? I'd rather just buy a cheap cable modem than buy a DOCSIS WIC for my Cisco stuff, any suggestions? A google search shows most cable modems now have built in routing and WiFi, which is fine as long as i can bypass it. I simply JUST want DOCSIS converted to ethernet, without all of the other stuff unless it can be disabled with ease. Thanks in advance for any suggestions!

--chris--

You will have to call Comcast and ask them to place the AIO router into bridged mode. This will achieve what you are trying to do.

Corndork2

You could try logging into the modem with username cusadmin and password cusadmin. Thats how I logged into my Comcast SMC gateway and put it in bridge mode. I had the same problem you did.

Also, please be aware your 1721 is going to bottle neck your connection like crazy. Whats your Comcast speed package? 25 down / 10 up or something like that?

The Cisco 1721 is (was really its EoL), and is only rated for 12,000 packets per second, which comes out to a little over 6Mbps. So, I really wouldn't recommend using it, unless you really want to. It would be a great learning experience, setting up addressing, NAT, DHCP, DNS, remote access, etc, but please be aware its going to slow down your throughput to Comcast as the 1721 is rated for less throughput than your DIA connection allows.

theodoxa

You could call Comcast (as mentioned above). That said, what I ended up doing in my case (stupid installer set mine up as a router and enabled the Wi-Fi even though I indicated I would be using my own router) is using Google. I managed to find the management IP for my Cable modem, allowing me to log in and put it in Bridging mode [and disable the Wi-Fi] myself.

jboogie81

Like corndork2 said, the Cisco stuff is too old to run daily. Thats why i dont want to have to call Comcast every time that i want to lab, and then AGAIN when i am done labbing. From what iv'e read, the SMCD3GNV is locked down by Xfinity/Comcast with a unique PW, so i think buying a cheap cable modem is my best option? It's just hard to find one nowadays that DO NOT ROUTE or include WiFi. Like i said, thats OK, but i need the opportunity to disable all the bells and whistles. Coax IN/one ethernet OUT is all i want, the dumber, the better. Lol...Thanks for the help guys. If anyone can vouch for a cheap cable modem that is compatible with DOCSIS 2.0 or later please let me know. Something like this maybe..... RCA Modem

--chris--

Like jboogie has mentioned, some of the new (maybe all?) AIO routers from comcast are locked down with admin passwords so that you are unable to move it into/out of bridge mode without a phone call. I just ran into this issue with a client setup Friday.

The usual cusadmin password gets you into the dashboard, but there are no options that will let you bridge once you are in their.

theodoxa

Probably too expensive ($345 New on Amazon.com) [and a bit of a learning curve,] but one option I really like is a Cisco ASA 5505 Firewall. It supports EIGRP, OSPF, OSPFv3 (Newest ASA OS only, I believe), RIP, Static Routing, ACLs, etc...and has sufficient throughput to not create a bottleneck.