Router – Locked out of our Comcast Business Gateway for seemingly no reason

router

Last fall we migrated our ISP from AT&T to Comcast at one of our offices. At that time, we received a new modem/router from Comcast and we configured everything to our liking. We've never really had very many issues with the router aside from having to restart it every once in a while.

About three months ago I changed the password on the router from the default. After that, I logged into the router several times to make changes with no issue. During May I logged into the router to add two new static routes, no problems. A week ago, I tried to log into the router and could not. I tried the non-default password that I changed it to, the default, anything and everything I could think of and no luck. I restarted the router on Monday thinking it may just be locked up, but after the restart it would still not let me log in.

This router is at our other office about 2 hours from here and I want to avoid having to drive down there and reset to factory defaults, reconfigure, etc…

Any ideas?

Best Answer

Assuming this was an SMC-branded Comcast cable modem, the usual cusadmin:highspeed username:password combination should work.

However, a safer long-term solution would be to use the Comcast-provided modem in "bridge mode" and install a proper router behind it. This will allow you to make the types of firewall rule and route changes you need without disrupting the cable modem's configuration. I've also seen the Comcast business class modems lose their configurations or get stuck in a strange state. I've replaced one unit at a client location eight times in two years.

Edit:

Comcast have also pushed out firmware that requires you to call them to reset the password to the cusadmin:highspeed combination listed above. This has played itself out on the Comcast Business Support Forums... - Sad.

Related Solutions

Router – Port forwarding with multiple IP’s

Configuring port forwarding on a 60B is a several step process. First you need to create a Virtual IP for the interface (WAN2) and IP (I assume 10.1.10.10) you want to forward. Then you have to add a firewall rule allowing traffic from the virtual IP to the internal interface. Can you confirm you've already done both of these?

Also, you mention that your static IP (with Comcast) remained the same. If this is the IP of the modem, I'd expect it to be an external IP, ie not in the 10.xx subnet. Yet the WAN2 interface of your Fortigate has a 10.xx address. This suggests you've got a double-NAT setup.

If this is the case you can fix it in one of two ways:

Setup port forwarding/NAT on the modem (ie actually use double NAT - not nice)
Change the modem to 'bridge mode' and have the Fortigate get the external IP as its WAN2 IP (better).

Note that with 2 if your Comcast connection is eg ADSL w PPP, you'll need to configure the Fortigate to do do the PPPoE authentication.

Double-NAt would also explain why changing the router broke things - the old router had port forwarding/NAT configured, but the new one didn't.

Edit:

It really sounds like my guess at the double-NAT scenario is correct. The DSL modem connected to WAN1 is getting the external IP address, and is assigning a 10.1.10.xx address to the Fortigate's WAN1 interface via DHCP. If the old modem definitely didn't have port forwarding then it was probably in bridge mode.

If you can't access the newly added modem via your internal network, I recommend you take the following steps:

Connect to the modem directly with an ethernet cable to eg your laptop
From your laptop, access the modem's configuration web interface. If you cant reach it, reset the modem to factory defaults and point your web browser at its factory set IP. This is guaranteed to get you to a config page, but will wipe existing settings.
Within the interface, set the modem's IP address to something inside your internal network's IP range.
Access the modem at the new IP, configure all the ADSL related settings (not authentication, just lower layer settings like encapsulation, VPI/VCI etc. Get these from Comcast if you dont have them.
Set the modem to 'bridge' mode. This is the important step.
If your ADSL connection uses PPPoE authentication, access the Fortigate admin page, and under Network -> Interfaces -> WAN1, select PPPoE and enter your ADSL username and password.

If this all works, you'll see WAN1 on the fortigate get an external IP address.

Router – How to set up daisy-chained routers for separate sub-nets

The general idea is you have your cable modem getting its external IP from the ISP, and you create an internal network that accesses that. The primary router(your modem) gets the larger net, we'll use a big one for simplicity ...

Router0/Modem
WAN: assigned via comcast
LAN: 192.168.0.1/16

Connect your modem/router to the subnet routers. If it's one of those SOHO things with multiple ports, those ought to work, if not you'll need a switch in between. Configure each router to be in the same subnet as the big one. to have a static IP in the subnet.

Router1
WAN: 192.168.1.1/16
LAN: DHCP scope: 192.168.1.1/24 - 192.168.1.254/24
Router2:
WAN: 192.168.2.1/16
LAN: DHCP scope: 192.168.2.1/24 - 192.168.2.254/24
...
Router5
WAN 192.168.5.1/16
LAN: DHCP scope: 192.168.5.1/24 - 192.168.5.254/24

/16 and /24 are 255.255.0.0 and 255.255.255.0 respectively. You should also not use the IPs I gave, security through obscurity thing.

Best Answer

Related Solutions

Router – Port forwarding with multiple IP’s

Router – How to set up daisy-chained routers for separate sub-nets

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