# Motorola SB5101 bridging setup



## ormond (Jul 30, 2007)

I'm trying to set up a Motorola SB5101 cable modem to bridge it's IP address to a Netscreen router.
The modem is in Manila, Philippines, and the local ISP who supplied the modem can't or won't help, and the local Motorola agent isn't much help, either.
The manual says that bridging can be set up by "authorised personnel".
Does anyone know how to do this?


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## JohnWill (Oct 19, 2002)

I don't see where the Motorola SB5101 has any NAT layer, so there's nothing to bridge: 

Motorola SB5101 User's Manual


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## TerryNet (Mar 23, 2005)

It would help if you could point us to the exact section of that manual.

I think that the confusion arises because on the Motorola Surfboard modems the USB and ethernet ports are already bridged. If you get multiple public IPs from the ISP you can have one computer connected via USB and (using a switch) about 30 connected via ethernet.

You already have a router so just connect it to the ethernet port and forget the USB.

If necessary get an ethernet card for the computer that needs it. The purchase price for one will probably be no more than about 4 or 5 months cost to get a second public IP (if your ISP even offers it).


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## ormond (Jul 30, 2007)

Thanks, but the manual (http://distributor.livas.lv/Motorol...Motorola_SB5100_Diagnostic_Modem_Overview.pdf) on page 16 shows a setting for whether bridging is enabled.
I'm not using the USB, the cable comes into the modem, an ethernet cable to the router (which is set up ready to vpn to home office) and I just need the IP address to go through to the router.


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## TerryNet (Mar 23, 2005)

Actually that page shows a sample log. The log for my Surfboard 4200 shows the same lines for "bridge" at this very moment. Like almost everybody I don't understand many details of those logs, which aren't meant for us anyhow.

Did you power cycle (unplug) the modem when switching from computer to router? You do have internet access with a computer connected to the modem, right?

Does that "set up ready to vpn to home office" maybe have anything to do with connection problems?


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## ormond (Jul 30, 2007)

Yes, we've powered down. I am actually in New Zealand and the modem is in The Philippines, so there is a five hour time difference and I can't check things right now. I've had it confirmed by Motorola New Zealand that bridging is "always on" for the SB5101. When they wake up in Manila I'm going to get a PC connected to the modem and use LogMeIn to see if I can make progress. Thanks for your help.


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## JohnWill (Oct 19, 2002)

When you're connected directly to the modem with a cable, let's see this.

Start, Run, CMD to open a command prompt:

Type the following command:

*IPCONFIG /ALL*

Right click in the command window and choose *Select All*, then hit *Enter*.
Paste the results in a message here.

If you are on a machine with no network connection, use a floppy, USB disk, or a CD-RW disk to transfer a text file with the information to allow pasting it here.


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## ormond (Jul 30, 2007)

I've now got someone to set up a machine connected to the router and when Manila is awake I'll get an ipconfig from them.
I assume that - if for the SB5101 bridging is always enabled, it must be configured somehow to know where to forward to.
No need to answer this just now, we've found an "expert" in Manila and will wait with interest.
Thanks for the help.


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## Memnoch322 (May 11, 2005)

a cable "modem" Is a bridge.


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## JohnWill (Oct 19, 2002)

According to the user's manual, the feature of choosing between using NAT or simple bridge mode is not always made available by the ISP.


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