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Contributor
Lebada
Posts: 15
Registered: ‎09-19-2011
Accepted Solution

Can't Change WAN Mac Address from Wireless Router ( Ubee Modem )

Here is my problem:

 

I have two internet lines connected to two separate desktop computers.

 

First line uses the Arris Modem, and is connected to a wireless router ( TP-LINK ). With this one I can change the IP via Clone MAC Address by changing the last digits of the WAN MAC.

 

Seconds line uses the Ubee Modem and is connected to the same wireless router ( TP-LINK ). The problem is I can't change the IP. When I go to 192.168.1.1. only the Factory MAC works, as soon as I change the last digit it looses connection completel and it won't connect to the internet. 

 

I actually have 2 TP Link Routers and tried both routers on both modems, and both work fine with the first line ( I can change IP's easily by changing the WAN MAC Address ), but none work with the 2nd internet line.

 

 

I can't seem to change IP's on this line at all. Only the Factory MAC of the router works.I need to be able to change IP's on this line and on this computer multiple times a day. Any solution?

 

 

 

 

( When I signed up for my 2nd internet line and plugged in the Ubee modem for the first time and wen thru the comcast setup process, it was on a friends laptop, maybe that has something to do with anything )

Contributor
Lebada
Posts: 15
Registered: ‎09-19-2011

Re: Can't Change WAN Mac Address from Wireless Router ( Ubee Modem )

It seems like I need to reset the Ubee modem each time I change the MAC WAN on my wireless router in order for the new IP to register.

 

How come the Arris modem does this on the fly without the need to restart it ?

 

Can I go the Comcast Store and change the Ubee modem for an Arris one?

Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: Can't Change WAN Mac Address from Wireless Router ( Ubee Modem )

Both modems should loose the connection when you chance the MAC address on the router's WAN interface.  It sounds like the config in the Arris is allowing more than one MAC address to talk at a time, like you are paying for more than one public IP address on that account.

 

If a cable modem is configured to only allow one MAC address, then you must power cycle it to get it to recognize a new one.  The only way around this for Comcast to change the config in the mode to allow more than on MAC address in the CPE table in the modem.  Look at http://192.168.100.1 for a listing of this table (most modems support this).

Contributor
Lebada
Posts: 15
Registered: ‎09-19-2011

Re: Can't Change WAN Mac Address from Wireless Router ( Ubee Modem )


Baric wrote:

Both modems should loose the connection when you chance the MAC address on the router's WAN interface.  It sounds like the config in the Arris is allowing more than one MAC address to talk at a time, like you are paying for more than one public IP address on that account.

 

If a cable modem is configured to only allow one MAC address, then you must power cycle it to get it to recognize a new one.  The only way around this for Comcast to change the config in the mode to allow more than on MAC address in the CPE table in the modem.  Look at http://192.168.100.1 for a listing of this table (most modems support this).

 

 

Can I do that? or do I need to call customer service or a technician? How exactly does it work.

 

 

 

I went to 192.168.100.1. but I have no options to change there.


 

Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: Can't Change WAN Mac Address from Wireless Router ( Ubee Modem )

You don't need it, simply power cycle your cable modem which wipes the CPE table and old MAc address.  Then when you go to get another DHCP lease, it will learn the new MAC address and henceforth talk to that router with the new MAC address.  If the modem is an EMTA (ie it has phone lines like the Arris), you need to reset the modem using the Reset button on the back since the device has internal batteries and pulling the power cord does NOT result in the device powering down.

 

While it may still be possible in some selected markets to get more than one public IP address (ie. a modem bootfile that allows more than one MAC address at a time), it's unavailable in most places with residential service.  Most folks don't need it because they can use a router, but for those who do, it is available as an option on business class service since this is what almost everyone who needs it uses (or should use).

 

You have no way to change the CPE table limit, almost all configurable parameters in your cable modem are locked down and controlled solely by Comcast.  When the modem first connects to Comcast it downloads a so-called bootfile that contains all the settings for that device model and your account.  One of these settings is the size of the CPE table, which is normally one.  This is how Comcast controls how many IP address you can get, if the modem will only talk to one MAC address, all others can't send anything else, all data is just dropped.  A typical home router simply masks all computers connected with it via a process called NAT (network address translation) and changes the outgoing data packets to look like they came from the router's WAN interface's MAC address, which is why that MAC address is the only one known to Comcast directly.

Contributor
Lebada
Posts: 15
Registered: ‎09-19-2011

Re: Can't Change WAN Mac Address from Wireless Router ( Ubee Modem )


Baric wrote:

You don't need it, simply power cycle your cable modem which wipes the CPE table and old MAc address.  Then when you go to get another DHCP lease, it will learn the new MAC address and henceforth talk to that router with the new MAC address.  If the modem is an EMTA (ie it has phone lines like the Arris), you need to reset the modem using the Reset button on the back since the device has internal batteries and pulling the power cord does NOT result in the device powering down.

 

While it may still be possible in some selected markets to get more than one public IP address (ie. a modem bootfile that allows more than one MAC address at a time), it's unavailable in most places with residential service.  Most folks don't need it because they can use a router, but for those who do, it is available as an option on business class service since this is what almost everyone who needs it uses (or should use).

 

You have no way to change the CPE table limit, almost all configurable parameters in your cable modem are locked down and controlled solely by Comcast.  When the modem first connects to Comcast it downloads a so-called bootfile that contains all the settings for that device model and your account.  One of these settings is the size of the CPE table, which is normally one.  This is how Comcast controls how many IP address you can get, if the modem will only talk to one MAC address, all others can't send anything else, all data is just dropped.  A typical home router simply masks all computers connected with it via a process called NAT (network address translation) and changes the outgoing data packets to look like they came from the router's WAN interface's MAC address, which is why that MAC address is the only one known to Comcast directly.


 

 

Actually I do need it for my business which is why I have two internet lines in my apartment, and that's why I'm asking for help here. I appreciate the detailed technological answer, however I need a solution. 

 

It's big inconvenience for me to reset the modem each time I change my wireless routers WAN MAC. With the Arris it takes 3 seconds, and I get new IP's.

 

Should I just go to the Comcast store and request to change the modem?

 

Thanks in advance, Baric.

Contributor
Lebada
Posts: 15
Registered: ‎09-19-2011

Re: Can't Change WAN Mac Address from Wireless Router ( Ubee Modem )

Exchanged it for an Arris modem, and now everything works perfectly as it should. 

 

Thanks Baric for the help.