How to access cable modem dashboard, when it's behind router?

[kape123]

Obviously, when I connect cable modem directly to laptop using LAN cable I can access it (http://192.168.100.1).

But when router is between my laptop and cable modem it's obviously not as easy as that... what I am wondering if there is a general approach on how to solve this? Forward some port on my router so that when I http://192.168.1.1:8080 from laptop goes to http://192.168.100.1:80 on my cable modem? How would I configure that on my router?

Router: Asus N66U router with custom Merlin firmware Cable modem: Motorola SB 6141

 

[coxhaus]

It should be available if you don't assign its' network on the LAN side. The modem is directly connected to the router so you should be able to enter the IP address. If you are using a 255.255.0.0 mask it will kill your access. I can type in 192.168.100.1 in a browser and my modem's web page pops up.

 

[jegesq]

Ditto. What Coxhaus said. I have no trouble accessing my cable modem from any device (wired or wireless) connected to my AC3200, which itself is directly connected to my Arris SB6183 modem using 192.168.100.1.

Sent from my SM-G900V using Tapatalk

 

[joegreat]

Same here: works with 192.168.100.1 for my Ubee cable modem behind the main router!

It's even documented in the manual of the modem - but it works only in case you have the modem in bridge mode (no router functionality on the modem).

 

[kape123]

It should be available if you don't assign its' network on the LAN side. The modem is directly connected to the router so you should be able to enter the IP address. If you are using a 255.255.0.0 mask it will kill your access. I can type in 192.168.100.1 in a browser and my modem's web page pops up.

OK, I think I've messed it up by stating "when it's behind router". Setup that I have is:

Coax outlet -> cable modem (192.168.100.1) -> router (creates network with 192.168.10.1 / 255.255.255.0) -> laptop.

I want to access cable modem dashboard using my laptop.

Looking through the settings, I've identified the problem - I've designated my laptop as DMZ (need to sometimes expose web server to external traffic because of development I am doing). Typing 192.168.100.1 on other machines I have in networks works like charm. Thanks for mentioning that 255.255.0.0 mask, that's what got me going.

Now that I am in this dashboard is there anything you guys recommend I do? Or I should leave it as is so I don't piss off my ISP? I don't seem to see the way to change anything anyway - dashboard doesn't offer to many options, but rather just displays Signal data.

 

[ColinTaylor]

As the cable modem is just a bridge there is usually nothing that can be changed. As you said, if you're lucky it will show you some stats and maybe a network log file. It can sometimes be useful for diagnosing problems with your ISP.

 

[jpclarke]

http://www.snbforums.com/threads/ho...with-different-subnet-mask.29468/#post-227985

 

[jpclarke]

Follow the steps I posted as it worked for me.

 

[ColinTaylor]

Follow the steps I posted as it worked for me.

No need. The OP has reported that's it's working now. The problem was his laptop being in the DMZ.

 

[mikeh2]

You may want to use your router to block access to the modem. Some modems are *not* read-only and you don't want anything malicious on your LAN to be able to communicate with the modem. For more, see
Using a router to block a modem
www.computerworld.com/article/2887243/using-a-router-to-block-a-modem.html

 

[nonsibuttavianulla]

Hi, I have the same issue with my RT-AC68U since upgrading to the 57 version, and still with 380.58_alpha3-gcf77301. As far as I remember, I never had to change any settings to reach to my VDSL modem. Asus router is at 10.0.0.1/24, while on the WAN port of the router is the VDSL modem with address 192.168.1.1. What has changed since version 57? What's the "vanilla" solution to this issue?
I checked that the modem is responding by connecting directly to it. The PPPoE connection is established directly by the Asus router.
Thanks

 

[jpclarke]

Hi,

Did you try the sub interface setup I posted above?

I had to do this to to get access to my draytek vigor 130 web interface through my ac-3200 on sky fibre vdsl.

Thanks

 

[mstombs]

It's usually only a problem connecting to a modem when using PPPoE on the router, you need a special route outside of the ppp tunnel - Tomato has a Web GUI function to 'route modem IP' to enable this, other firmwares have needed a few script commands see for example
https://www.dd-wrt.com/wiki/index.php/Access_To_Modem_Configuration
When using a 'half-bridge' type cable modem with dhcp on WAN you shouldn't need any special configuration as long as LAN and WAN address ranges are distinct and you are not using a VPN. I wouldn't be surprised if some router firmwares did not forward 'non internet routable' private IP addresses which likely get dropped by your ISP, which apart from accessing your ISPs infrastructure would only be 'leakage'.

 

[cosmoxl]

I couldn't connect to my cable modem because of an openvpn client policy routing rule forcing all LAN clients through the VPN. I had to create a separate rule allowing lan clients to reach 192.168.100.1 via the WAN.