04-23-2011 12:38 PM
I am trying to use my own router with my motorola modem, but I am having some issues. This is what I've done:
1. Reset modem
2. Connect laptop to modem.
3. Disable NAPT by goign to setup->basic->NAPT mode-> disable (I think now it is in bridging mode)
4. Reset ASUS router
5. Connect laptop to router
6. Change LAN IP to 192.168.0.1, keep everything else the same. WAN side is in DHCP mode. DHCP is enabled for the LAN side.
7. Connect router WAN side to the LAN port of the modem.
This is what I see:
1. Router recieved WAN DHCP lease
IP: 188.8.131.52 /255.255.252.0
Default route: 184.108.40.206
2. From PC, I can ping the router (192.168.0.1), but nothing in the internet side (220.127.116.11, 18.104.22.168)
2. From modem (accessed through 192.168.100.1), I can ping the router, but nothing else in the internet side.
I know I can either just use internal router in the motorola modem or plug in my router and live with double NAT, but I would rather not do that. Anyone have suggestions what I can try next? Thanks.
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04-23-2011 01:20 PM
Funny you should say that. I had a plain old modem in my previous apartment. I cancelled comcast service and they insisted my modem belongs to them. Unless I gave it to them, they would charge me. Now I got a new one through comcast offers and this is what they gave me. So, yea, I would love to have the old one back but I am stuck with this new one.
04-23-2011 01:47 PM
Don't think NAPT is the Same as NAT.
I think port translation has to do with gaming and disabling it does not get you into Bridge mode.
Here is a link to the User Guide. You can probably do what you want to do.
04-23-2011 02:52 PM
The SBG901 is NOT a cable modem, it's a router/modem combo and should NOT be given out as a plain modem. They usually give this device out to people who payed for the Home Networking service, or who took some kind of freebie/discount offer for a router. Neither is a good deal, IMHO. If the sbg901 is yours outright (freebie or bought from Comcast), just call Comcast and tell them you want to rent a regular cable modem. Better yet, buy your own and save the rent you pay Comcast. Either way, get rid of the SBG901.
If general, if they provided the modem, it belongs to them, you just rent it. When you move or cancel your account, you have to return it, just like your cable settop box or remote, etc. If you actually bought the modem, then make sure you keep the receipt to prove that. If you replace their modem with your own, make sure you turn their modem back in (and get a receipt) or you can have trouble further down the line.
04-23-2011 03:18 PM
No argument here, but If he owns the combo gateway then he could perhaps turn off the DhCP function and effectively turn it in to a bridge????
If he is renting it, he can trade it in for a regular modem.
04-23-2011 03:27 PM
I own the modem. It was a freebe from comcast offers.com.
If I turn off the DHCP on the modem and hook up a router to it, then I would essentially be double natting. E.G. public ip -> 192.168.0.x (motorola modem) -> 192.168.1.x (my router) Some software have problems with double natting, plus I would have to port forward twice for services I want to expose. That is not the ideal case.
I spent all morning on this and I give up. I'm turning my two asus routers into switches and use them to connect to the motorola modem. Although I would rather have all the functionalities of ddwrt on the asus. Thanks for the help.
04-23-2011 03:36 PM
Yes, it's technically possible and that's what he tried. The fact that his Netgear router pulled a public IP from Comcast says it's talking out, but not very far. That it works with the laptop direct connection but not the router indicates either a Netgear router issue, or possibly a compability issue with the router connected to the SBG901. It's a funky setup that I would not recommend except as an experiment.
Now if the problem is in the Netgear router, swapping in plain cable modem won't work, but it's a quick thing to try since it's only $2 or so for the month for the modem. Then he can either continue using the new modem, or get his own.
04-23-2011 03:51 PM
Thanks, Baric. Please ignore my previous post. It was meant for another thread.
I will hunt down a dedicated modem and try it. I'm sure it will work because I used the same setup in my previous apartment.
04-25-2011 08:43 AM
Don't forget that with the sbg901 AND the netgear router in play, there are two routers involved, and potentially two hardware firewalls. The IP addresses that devices connected to the Netgear router will get are unknown to the motorola router, as the netgear router acts as their DHCP server. A static route will be required on the sbg901 to allow it to know where to forward return traffic from internet hosts. The Netgear router, when conncted to the sbg901, should get a DHCP supplied address on it's WAN port in the sbg901's LAN subnet range....unless these dual purpose devices work differently than a seperate router and modem setup.
It looks like you can disable the router/gateway function of the sbg901 in the Advanced Options page, by enabling Rg PassThrough. I believe this will allow you to use the unit as a modem only, and connect the Netgear router's WAN port to the LAN port on the sbg901, and get a public IP on the netgear, effectively putting the sbg901 in bridged mode...
I don't work for Comcast...
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06-26-2011 02:16 AM
08-02-2011 09:57 PM
This is really helpful. I did not do "Changed gateway IPAddress from default (192.168.0.1) to match the same subnet as Linksys router." because I do not quite understand how to get the subnet from the router, but everything still works perfectly! Btw, I am using D-Link N300. Hopefully it would be helpful for the people saw this thread later. =)
09-06-2011 03:33 PM
this post is very helpful, and i had to do some research the user and pass for the motorola page is user: admin, password: motorola, make sure you change it when logged in. thanks for this post
09-29-2011 01:36 PM - edited 09-29-2011 01:37 PM
This apparently has become such a big issue that as of today, Comcast is including a special recorded message when you call tech support on how to fix it while you are waiting for a tech to answer
12-27-2011 12:54 PM
Actually it is a lot simpler and I went a little more careful on the security bit.
Do not disable WAN blocking. Doing so will expose your internal network to the WAN and you really do not know who is out there looking at your stuff.
Notice that I did not make a lot of changes. It migh look like a lot of settings but they are optional. You really need to stop DHCP, Disable NATP and Enable Rg PassThrough. Do not have to change the default IP either.
If you have diabled WAN Blocking - I recommend that you enable it immidiately. Be safe and be sure.
01-03-2012 08:14 AM
Thank you. Hats off to the ifnormation... You guys saved me alot.
I was so worried that I paid so much money on the router (which worked well with ATT DSL Modem) and didnt work with this Comcast cable modem/router combo device.
02-08-2012 12:28 PM
The Motorola SBG901 (modem with G wireless) can be connected with most wired/wireless N routers. First, follow the directions provided by Comcast under their online Networking 101, called 'Things to Remember When Setting up or Changing Your Home Network.' Comcast says in this article to release the IP configured for your Comcast Cable modem before trying to link a router. Ultimately, what you end up with is two wireless systems running side-by-side: a G wireless and an N wireless, and, or course, your 4 wired ports available on the N router. Yes, wireless devices in your home will 'see' both WIFI's - take your pick. I am not an expert; I just did the relase first.
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