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R.A. McConnell
R.A. McConnell, Network Admin
Category: Networking
Satisfied Customers: 757
Experience:  A-Plus, MCP, 18+ years experience, LINUX admin
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I use a Motorola SBG6580 modem gateway, and I have been trying

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I use a Motorola SBG6580 modem gateway, and I have been trying to find the section in the configuration page which will enable me to bind an ip address to the mac address, but I can't find it. It is probably there, but called something else. Could you please tell me where to find it and how to do it please?
Hello, I'll be happy to help you with this. Those Motorola cable gateways that can reserve addresses in DHCP access the settings like this:

  1. Login to the web-based configuration utility.

  2. Click on LAN.

  3. Click on dhcp leases.

  4. Enter the IP address and MAC address that you want to pair up together, and provide the computer with a name.

  5. Click Add.

If you don't see the dhcp leases option, you can't reserve them on this model and you'll have to manually assign an IP address outside of the range being distributed by your DHCP server. If you need to do this and would like some help with it, let me know and I'll be happy to lend a hand.
Customer: replied 6 years ago.

The mac address that I bind to the ip address should be the LAN mac address. Is that correct?

The computer already has a lease, but the MAC address is different from the LAN mac address.

Even though DHCP is enabled as per Time Warner's directions, I want the IP address to be unchanged when the lease expires, so I should bind the LAN's mac address to an ip address for the computer to keep the same ip address. Is that correct?

Typically a station that receives and address via DHCP will attempt to renew the lease on that address when its expiration time is half up. I assume that you're referring to the IP address of a computer on your home network, and not the address of the Motorola unit itself. Is this correct?
Customer: replied 6 years ago.
I build my own computers and know them inside and out, but networking is not even close to my area of expertise. Maybe you have already figured this out and maybe you haven't, but I am trying to correct a NAT problem on VUZE which is a file sharing program. It says that it is firewalled, and the way to fix this problem is too either disable DHCP (which I can't do) or use the mac adress binding capabilities of the router to assign a specific IP to the netwok card. Hopefully this will clear up exactly what I am trying to do. Thank you for your patience if this takes a while.
No problem. Being an expert in one field doesn't necessarily make you an expert in any other. With this in mind, let me repeat what I believe you're trying to do, so that I can make sure that I get you the correct answer:

You have a computer on your local network, connected to the Motorola cable gateway, and you want to allow a computer or computers outside your local network to have access to a file sharing service on it. As such, you need the computer on your local network (which is using a NAT/firewall setup which is controlled by the router, as most computers behind a router do) to have an IP address that does not change, so that you can open the hole through the firewall to allow it to work. Is that correct?
Customer: replied 6 years ago.
I have one desktop computer which is hard wired to the Motorola Cable Gateway. There are no other computers on my network except for 2 laptops that connect wirelessly, but they are usually shut down, so it is only the desktop that I am concerned with being able to send/receive to and from other computers. Actually the firewall in NIS 2010 is configured to allow traffic to and from the VUZE program, and Windows Firewall is turned off. I have also disbaled the firewall in the Motorola too. Yes, I know that sounds like a precarious setp, but NIS 2010 has been very good stopping viruses and unwanted attempts to enter my computer so far. I don't keep super sensitive info on my computer, so I am not that worried.
This configuration step is posted as an answer, per site policy, but don't accept it until you're satisfied that it has answered your original question.

An easy way to do this is to set your desktop to use a manual IP address outside of the range that the Motorola box normally distributes, re-enable the firewall on the Motorola box, then set your desktop's IP address as the DMZ. What this does is still allow the Motorola box to control network access (doing otherwise in the modern day is mind-bogglingly dangerous), yet all unsolicited incoming traffic will automatically be sent to your desktop, removing the need to do additional configuration of the Motorola's firewall to allow only some incoming traffic (because you're using NIS to manage the security on the desktop).

Do you know how to check the range of addresses that the DHCP server in the Motorola unit is using? If so, go ahead and check. If not, let me know and I'll be happy to help.
Customer: replied 6 years ago.

The range is to Should I set the ip to lets say first or set the DMZ address to When I try to set the ip to 275 first it says .....


Error converting one or more entries:

Possible causes of this error:

1. IP address is already in use by client with another MAC address

2. IP address already exists in the DHCP lease reservation table

3. The IP address is invalid. It must be between and


When I try to set the DMZ address to it doesn't appear to take it.

There are currently no DHCP clients setup with any MAC address.

First, try resetting the DHCP range for through and then assign to your computer (manually). When you are confident that you can browse the web with that IP address, set it as the DMZ (

The address is invalid, as the numbers in an IP address can only be zero through 254.
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Customer: replied 6 years ago.
It said the starting local address was, and there were 253 CPEs. Can I assume that changing the CPEs to 250 was resetting the DHCP range? After I did that I used the LANs mac address and binded it to and it accepted it. I then set the DMZ host to and it accepted that too. I also re-enabled the Motorola firewall too. Does that sound like I did it correctly?
That sounds like you did every thing correctly. Excellent job! Since you're on the web, we can verify that this is working. Can you test your VUZE software now? If it's working, then we're probably done. Let me know.
Customer: replied 6 years ago.

Can I get back to you tommorow?

Are you there on saturdays?

If not is it ok if I get back to you on monday?

So far it looks ok with a green NAT light instead of a red one, but I would like to give it a little more time to see if it stays that way. Is that ok?

Monday would work better, to be sure. It's pretty unlikely that I'll be in at all on Saturday. Let me know if you have any trouble with this and I'll be happy to help on Monday.
Customer: replied 6 years ago.
Thank you very much for what appears to have solved my problem. I will get back to you on monday.

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