Changing IP Address on Virgin

[Ignitionnet]

Originally Posted by jem

No it doesn't have to work. The frequency of IP address changes can be limited. Think of it this way, suppose I decided to spoof my router's MAC address every five minutes and get a new IP. How long would it take me to use up the entire set of DHCP leases?

I think his point was that changing the MAC address must result in a new IP address being issued under normal circumstances. The implication was that it wouldn't always work and that there are a limited number of changes permitted which isn't the case. So long as the hosts table isn't full for that modem a MAC address change must result in a new IP address.

[BenMcr]

My bad on how I phrased it - sorry

[eth01]

Originally Posted by jem

No it doesn't have to work. The frequency of IP address changes can be limited. Think of it this way, suppose I decided to spoof my router's MAC address every five minutes and get a new IP. How long would it take me to use up the entire set of DHCP leases?

you don't understand VM's network properly or the way it works.

[Russell Winder]

Finally, I managed to change my IP address. I spoofed the MAC address in the rooter and voila. Connected with a laptop directly, it changed the IP address too.

Very strange indeed. I was stuck with the same IP addy for several months now. I had tried the above several times with no success....

[tweetiepooh]

If you are developing software that checks IP's you would be better running the servers on your LAN and simply changing the IP's locally.

As people have shown masking the IP on internet traffic isn't difficult.

[DJ-Shadow]

Hello
Changing your router randomly to another MAC address can be very dangerous as if you happen to choose a MAC address already in use on the network then you will cause network issues with Virgin Media, the MAC address should be only changed to one that you already own to stop this problem. VM could even go down the route of banning you from their network.
Mike

[AndyCalling]

That would be true if you were changing the MAC address of the modem, but surely not when changing the MAC address of the router?

[Stuart]

Originally Posted by DJ-Shadow

Hello
Changing your router randomly to another MAC address can be very dangerous as if you happen to choose a MAC address already in use on the network then you will cause network issues with Virgin Media, the MAC address should be only changed to one that you already own to stop this problem. VM could even go down the route of banning you from their network.
Mike

That's the modem MAC you are referring to. The Router MAC can be changed multiple times to pretty much anything you want.

[DJ-Shadow]

Hello
No if you look up your external facing IP address it is the same as your router and not your modem, as the MAC address of your router is registered on the VM network.

In days gone past you had to register your PC or routers MAC with BY, NTL or TW on their network, this was to stop spoofing.

"You *can* have two MAC addresses in a LAN. It's called MAC spoofing and it can be used to get traffic intended for another host to the spoofed one.

If you have two identical MACs on a network, all of the traffic intended for one will go to another, causing weird stuff to happen. This is true whether it be a switch or a hub. As far as I can tell, collisions such as these aren't checked for the same way IP address collisions are.

Computer attackers spoof MACs so that they can see what traffic is going to other computers. Anything that's not encrypted can be sniffed, so if you authenticated to a website with HTTPS and then it switched to HTTP, they could see all HTTP traffic in cleartext."

Again nope as the routers MAC address is registered not just with the modem but also with the VM network and as stated above you could get data from somebody else, and would be in breach of DPA.

Regards Michael

[Toto]

Originally Posted by DJ-Shadow

Hello
No if you look up your external facing IP address it is the same as your router and not your modem, as the MAC address of your router is registered on the VM network.

Explain please? How can you look up your external facing IP address?

In days gone past you had to register your PC or routers MAC with BY, NTL or TW on their network, this was to stop spoofing.

No that is not quite true. I can't speak for the Blueyonder network, but you never had to register your PC/Router MAC address for the Langley part of the ntl network, only the Bromley part.

"You *can* have two MAC addresses in a LAN. It's called MAC spoofing and it can be used to get traffic intended for another host to the spoofed one.

If you have two identical MACs on a network, all of the traffic intended for one will go to another, causing weird stuff to happen. This is true whether it be a switch or a hub. As far as I can tell, collisions such as these aren't checked for the same way IP address collisions are.

Computer attackers spoof MACs so that they can see what traffic is going to other computers. Anything that's not encrypted can be sniffed, so if you authenticated to a website with HTTPS and then it switched to HTTP, they could see all HTTP traffic in cleartext."

I think the mechanics of this network set up needs better explaining.

Again nope as the routers MAC address is registered not just with the modem but also with the VM network and as stated above you could get data from somebody else, and would be in breach of DPA.

By registered I assume you mean automatically on the CMTS, not through some sort of registration page by the end user or VM employee?

[DJ-Shadow]

Hello
To find out your IP address that is facing the internet it is http://www.whatismyip.com/, your router has 2 IP addresses Internal Lan and Wan, the WAN one is gathered from the VM network, if you look at the logs for any DHCP server that gives IPs it has registered your MAC address of the router.

All the modem does is change the cable and signal types, has only one IP (Internally facing), Your UBR see this MAC address, If you do a tracert to google.co.uk you will see from your PC to Router and then to UBR.

Your routers MAC address is also registered at the UBR (Universal Broadband Router) routers dont work on IP addresses but on MAC tables inside of the hardware.

Mike

[Toto]

Originally Posted by DJ-Shadow

Hello
To find out your IP address that is facing the internet it is http://www.whatismyip.com/, your router has 2 IP addresses Internal Lan and Wan, the WAN one is gathered from the VM network, if you look at the logs for any DHCP server that gives IPs it has registered your MAC address of the router.

All the modem does is change the cable and signal types, has only one IP (Internally facing), Your UBR see this MAC address, If you do a tracert to google.co.uk you will see from your PC to Router and then to UBR.

Your routers MAC address is also registered at the UBR (Universal Broadband Router) routers dont work on IP addresses but on MAC tables inside of the hardware.

Mike

Sorry, I understand what the cable modem does, but I am not sure what you were trying to explain to Stuart C, who correctly said:

That's the modem MAC you are referring to. The Router MAC can be changed multiple times to pretty much anything you want.

You then said:

Hello
No if you look up your external facing IP address it is the same as your router and not your modem, as the MAC address of your router is registered on the VM network.

I'm just trying to work out what your point was.

[DJ-Shadow]

If you change the routers MAC to a MAC address already on your part of the VM network then the UBR will send the data to both addresses. Yes it can be changed multiple times but you have to be careful as each MAC address is tied to a device so in Randomly changing it there is a chance you could choose one that is already in use on that part of the VM network.


Mike

[Peter_]

Originally Posted by DJ-Shadow

If you change the routers MAC to a MAC address already on your part of the VM network then the UBR will send the data to both addresses. Yes it can be changed multiple times but you have to be careful as each MAC address is tied to a device so in Randomly changing it there is a chance you could choose one that is already in use on that part of the VM network.


Mike

And once you get to 4 MAC addresses your connection is blocked as the host table is full.

[Stuart]

Originally Posted by DJ-Shadow

If you change the routers MAC to a MAC address already on your part of the VM network then the UBR will send the data to both addresses. Yes it can be changed multiple times but you have to be careful as each MAC address is tied to a device so in Randomly changing it there is a chance you could choose one that is already in use on that part of the VM network.


Mike

However, with the number of possible MAC addresses (which is in the billions), the chances of you choosing one that is attached to your UBR are cosiderably lower than your chances of winning the lottery.