RWildThem Or Us Premium Member join:2003-09-15 Cary, NC |
RWild
Premium Member
2008-Aug-6 8:16 pm
[TWC] How to Disable DHCP on Surfboard Modem?The problem I have been having with my Roadrunner connect dropping could be related to the fact that the Motorola modem is apparently competing with my dual WAN router as a DHCP server. On those rare occasions that I can actually modem, there is no option to disable LAN side DHCP. How can I do this? |
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sivranVive Vivaldi Premium Member join:2003-09-15 Irving, TX |
sivran
Premium Member
2008-Aug-6 9:02 pm
What model of modem is this? |
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MacLeechThe one and only Premium Member join:2001-07-14 SoCal |
to RWild
Unless the modem is one of the SBG router models you can't disable the DHCP server. It should only be used anyway when the modem loses contact with the cable company and can't be configured in bridge mode during the sync process. |
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RWildThem Or Us Premium Member join:2003-09-15 Cary, NC |
RWild
Premium Member
2008-Aug-7 7:07 am
I am not talking about the WAN side. When I can access the modem, one of the screens says that I can connect xx computers - that is, on the LAN side the modem wants to be a DHCP server. This means it is competing with by router as a DHCP server and will do so whenever it is powered up. |
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hobgoblinSortof Agoblin Premium Member join:2001-11-25 Orchard Park, NY |
said by RWild:I am not talking about the WAN side. When I can access the modem, one of the screens says that I can connect xx computers - that is, on the LAN side the modem wants to be a DHCP server. This means it is competing with by router as a DHCP server and will do so whenever it is powered up. What model is it? Hob |
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MacLeechThe one and only Premium Member join:2001-07-14 SoCal 2 edits |
to RWild
 Screen from MY Motorola SB5101 |
said by RWild:I am not talking about the WAN side. When I can access the modem, one of the screens says that I can connect xx computers - that is, on the LAN side the modem wants to be a DHCP server. This means it is competing with by router as a DHCP server and will do so whenever it is powered up. I'm not talking about the WAN side either. Standard Moto SB modems (not their SBG router modems) have a DHCP server in them that is bypassed when the modem is sync'd with the cable system correctly. The only time you should get a IP (in the 192.168 range) from the modem is when the modem is NOT connected to the cable system properly. As soon as the modem is connected to the cable system properly the modem is put into bridge mode and the DHCP server in the modem is bypassed so the cable company DHCP server can issue an IP to the computer or router connected to the modem. The screen (» 192.168.100.1/config.html) that says you can connect xx computer is showing you how many computers the modem is configured to allow online by the configuration file downloaded by the modem when it sync'd to the cable system. Otherwise it's telling you how many computers are supported by the LAN feature when the modem is not online. Read the screen on the modem again: quote: When the Cable Modem is disconnected from the Internet, users on the LAN can be dynamically assigned IP Addresses by the Cable Modem DHCP Server.
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RWildThem Or Us Premium Member join:2003-09-15 Cary, NC |
to hobgoblin
Don't know what model. It's currently dead so can't access it and I am not physically there. Won't be able to answer this for a week or so. |
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| RWild |
to MacLeech
The screen looks familiar. Thanks for the explanation. |
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sivranVive Vivaldi Premium Member join:2003-09-15 Irving, TX |
to MacLeech
Is that page only accessible when the modem is not synced? |
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MacLeechThe one and only Premium Member join:2001-07-14 SoCal 1 edit |
MacLeech
Premium Member
2008-Aug-7 1:50 pm
said by sivran:Is that page only accessible when the modem is not synced? Every Moto modem I've used always has it accessible, but I know ISPs could write custom modem configuration files to block it if they really wanted to. |
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pizzOld man. Who loves video games Premium Member join:2000-10-27 Astoria, NY |
pizz to RWild
Premium Member
2008-Aug-7 2:40 pm
to RWild
Man kinda wish i kept my Moto EMTA  Didnt even know it had that feature, pretty niffty. |
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Vchat20Landing is the REAL challenge Premium Member join:2003-09-16 Columbus, OH |
to RWild
Like MacLeech stated, and it's quite simple to understand: This 'routing' feature is only enabled if the cable company allows it. TWC thus far has anything like this disabled and sends the external ip to your computer's NIC. You can ONLY connect one machine to the LAN port of the modem without a router. The only time you will get a local 192.168.x.x ip from the modem is if it never sync'd in the first place. All modem's do this. Once the modem syncs though, it downloads a config file that TWC has provided (you CANNOT bypass this without illegal means) which disables functionality such as this routing function. Buy a cheap $40 router and throw it between the modem and your pc's. Save yourself a headache. |
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