Proper way to access Cable Modem Configuration page through router

[DDR4040]

Sorry for the really basic question, but it has been bugging me for a while. My cable modem is a Linksys CM100. The default configuration webpage is located at 192.168.100.1. It is connected to a Linksys WRT610n. The configuration page for that is located at 192.168.1.1. My DHCP server is setup to start at 192.168.1.100 and allows 10 users.

My problem is accessing the CM100's configuration page. Somtimes it will connect and I am able to check my logs. The majority of the times though, it times out. I have tried using both Firefox and IE8 with the same results. I know I can access the modem if I disconnect it from the router and plug it directly into my laptop. My real question is why is it able to connect sometimes but not others? Is the problem due to using the default addresses? Is there a setting on the WRT610n that I need to change? The part that has me scratching my head is that it randomly decides to connect. I was able to get through 3 or 4 times last week with no problems. If something was misconfigured on the router, wouldn't that block my access 100% of the time? I unplugged all of my computer equipment on Saturday when a severe thunderstorm rolled through and haven't been able to get into my modem since then. I haven't touched any of the settings on my router or modem in months. My internet, wireless and networking are all working perfectly. I just can't access the modem webpage. Any suggestions or advice? Thanks.

 

[kurtsee]

Can you get to the Web Admin page of the CM100 with your computer directly connected to its LAN port?

I am guess the routing table on the WRT610n gets updated sometimes to a blackhole and other times to the Web Admin page of the CM100. Why? Not sure.

If the routing table is the cause, adding a static route on the WRT610n will solve this. Or else I am guess its time to replace the CM100.

-Kurt

 

[YeOldeStonecat]

I'd check the firmware version on the cable modem, and check your web browser for un-necessary toolbars and perhaps clear temp internet files.

It should be no problem accessing your cable modems web admin page from behind your own router, the fact that they're on different IP ranges is not a problem, since it's a different network (192.168.100.xxx)..your router will direct that traffic out the WAN port since it's a different network than the inside (192.168.1.xxx).

The fact that you were able to access it at least once shows it's not a network design issue, else it would not work the first time period. So don't spend time chasing down routing tables or firewall rules on your router.

Sounds like the cable modem is about ready to jump off the cliff. Replace it with a good Motorola Surfboard!