[SOLVED] MAC Address IP change question

[Miroslav Nikolov]

Ok. So I looked at a video online, talking about how you can change your IP address by changing your router's MAC address. It seems to work for me, but I have a question.

I did this many times, just to get a clear understanding, and what I found out is that it only really changes the last 2 sets of digits of the IP. (Btw, when I say IP, I am referring to my public IP in ipv4 format).

I read online that the first 2 sets of digits of the IP are called the "network part", and the second 2 sets of digits are called the "host part", but I don't really understand what that means exactly. Here are my observations visualized:

Starting IP:
154.131.112.43
After changing MAC:
154.131.118.39

As you can see above, after changing the MAC of my router, only the last 2 sets of digits from the IP change - the host part. The network part - the first 2 sets of digits do not change.
During my tests, they did change sometimes, but from what I found out, there are 3 or 4 different variations that are ALWAYS used, no matter what, so I don't consider that a change. For example:
154.131
65.142
207.32


So my question is, since only the last 2 sets of digits are really changing, are all the IPs I'm getting DIRECTLY related to each other ?

 

[USAFRet]

You're completely off-base with this. Don't know what video you watched, but they are operating with grave misunderstandings.

What device did you change the MAC address of?

 

[bill001g]

It is actually not that simple. Without going into a huge education post the ips that are assigned are based on the subnet mask. It is not always the last 2 sets of digits. In the most common case it can be just the last set but it can be must more complex like just parts of what you are calling "digits".

Still I suspect more your question is how they are related. The IP addresses are assigned in blocks to ISP. They can only give customers IP blocks they control. The ISP then can in different neighborhoods break the block of ip into smaller blocks. Say they assign 500 addresses to your and y our neighbors. You can get any one of those ip but not ip from other ISP or even other blocks your ISP owns and chooses to use in other cites.

This is partially how the geolocation of IP works. Say if you given a IP that ends in ZZ and then you are give a IP that ends in YY. Since the first part of the IP is the same the software thinks...wrongly many times...that all these IP are in city xxxxx

The mac address trick does not work on all systems. I know on many cable systems the ip is assigned based on the mac address of the modem on your account. Changing the router or pc connected to the modem does not get a different IP. You generally need to leave the modem turned off for long periods of times to hope to get lucky and get a different IP assigned.

 

[Miroslav Nikolov]

You're completely off-base with this. Don't know what video you watched, but they are operating with grave misunderstandings.

What device did you change the MAC address of?

My router, which is connected to a modem. In the video that I watched, it basically said that when you change the MAC address of your router, it makes the modem think that you connected a new router and it gives it a new IP. And that's how the whole thing works.

 

[Miroslav Nikolov]

It is actually not that simple. Without going into a huge education post the ips that are assigned are based on the subnet mask. It is not always the last 2 sets of digits. In the most common case it can be just the last set but it can be must more complex like just parts of what you are calling "digits".

Still I suspect more your question is how they are related. The IP addresses are assigned in blocks to ISP. They can only give customers IP blocks they control. The ISP then can in different neighborhoods break the block of ip into smaller blocks. Say they assign 500 addresses to your and y our neighbors. You can get any one of those ip but not ip from other ISP or even other blocks your ISP owns and chooses to use in other cites.

This is partially how the geolocation of IP works. Say if you given a IP that ends in ZZ and then you are give a IP that ends in YY. Since the first part of the IP is the same the software thinks...wrongly many times...that all these IP are in city xxxxx

The mac address trick does not work on all systems. I know on many cable systems the ip is assigned based on the mac address of the modem on your account. Changing the router or pc connected to the modem does not get a different IP. You generally need to leave the modem turned off for long periods of times to hope to get lucky and get a different IP assigned.

Ok thanks. This was actually very helpful now that I read it again.

 

[USAFRet]

My router, which is connected to a modem.

Right.

MAC addresses are (mostly) unique. There have been a few collisions.
But, the manufacturer is the first part of it, then maybe device type, then the specific device. This is not set in stone, but a mostly agreed upon concept.

Change the MAC address, your ISP sees a "new" device. And assigns it an IP address out of its pool.
And can only be one that it has control over.
Conceptually, think of the 4 octets in your public IP address as Town.Neighborhood.Street.House.
You can only change the 'town and neighborhood' if you change ISP providers.

But your public IP address is really of no consequence.

 

[Miroslav Nikolov]

Right.

MAC addresses are (mostly) unique. There have been a few collisions.
But, the manufacturer is the first part of it, then maybe device type, then the specific device. This is not set in stone, but a mostly agreed upon concept.

Change the MAC address, your ISP sees a "new" device. And assigns it an IP address out of its pool.
And can only be one that it has control over.
Conceptually, think of the 4 octets in your public IP address as Town.Neighborhood.Street.House.
You can only change the 'town and neighborhood' if you change ISP providers.

But your public IP address is really of no consequence.

Ok thx. This was very helpful too.