Change public ip address

[DirtyDan1337]

I'm using an xfinity gateway and a d link dir 842 in bridge mode. I want to change my public ip address, is there anyway I could do that with my setup? Thanks!

[Willowwizard]

Maybe someone here with more knowledge about specifically Xfinity Gateway modems might be able to chime in here and suggest a better way.

 

Generally if you completely unplug your modem for a few minutes and plug everything back in, the ISP should give you a new IP address as your old one gets snatched up by someone else. There isn't a way to specify what public IP address you want assigned to you unless you pay for a business/enterprise internet package.

 

EDIT: I almost forgot. It's also possible to 'change' your public IP address by using a service often sponsoring LTT; VPNs.

VPNs like Private Internet Access and etc. allow you to connect to the internet through their servers (with everything encrypted of course) and essentially 'change' your public IP address to the IP address of their servers.

[Donut417]

38 minutes ago, DirtyDan1337 said:

I'm using an xfinity gateway and a d link dir 842 in bridge mode. I want to change my public ip address, is there anyway I could do that with my setup? Thanks!

If your using the Xfinity gateway in modem/router mode then probably not. As they dont support Mac address cloning. Your best bet is to look in the settings and find out how long the DHCP lease is for on your public IP, you need to make sure your modem is turned off and wait for the lease to expire. If your lucky you may get a new IP. Comcast assigns IP's based on the MAC address of what ever is connected to the modem. If your case your modem and router are one unit. 

 

For me, I own my own standard modem Non gateway bull shit.. If I were to change the router I had connected to my modem I would pull a new IP address from Comcast. 

[AbsoluteFool]

49 minutes ago, Donut417 said:

If your using the Xfinity gateway in modem/router mode then probably not. As they dont support Mac address cloning. Your best bet is to look in the settings and find out how long the DHCP lease is for on your public IP, you need to make sure your modem is turned off and wait for the lease to expire. If your lucky you may get a new IP. Comcast assigns IP's based on the MAC address of what ever is connected to the modem. If your case your modem and router are one unit. 

 

For me, I own my own standard modem Non gateway bull shit.. If I were to change the router I had connected to my modem I would pull a new IP address from Comcast. 

DCHP is for local IP not public.

1 hour ago, DirtyDan1337 said:

I'm using an xfinity gateway and a d link dir 842 in bridge mode. I want to change my public ip address, is there anyway I could do that with my setup? Thanks!

You'll have to contact your ISP or wait for the TTL to run out from your ISP side.

[Donut417]

11 minutes ago, AbsoluteFool said:

DCHP is for local IP not public.

You'll have to contact your ISP or wait for the TTL to run out from your ISP side.

DHCP is a server that assigns IP address. Comcast does not do Static IP's  for residential customers. So YES, Comcast uses a DHCP server. And yes your router has a built in DHCP server for your home network. The picture below is to my modem, Not a modem/router, standard no bull shit cable modem. See the part about DHCP? Because Comcast has a DHCP server they use the assign Dynamic IP's to their customers. 

Cable Modem

Status	Signal	Addresses	Configuration	Logs	Open Source	Help

This page provides information about the startup process of the Cable Modem. If there is a problem with the startup, the word "Failed" may appear in the Status column. Should this occur, visit the Help area and perform the Checkup procedures listed there. If the problem continues, click on the word "Failed" for more detailed information about the failure, or call your service provider for assistance.

---

 

Task	Status
DOCSIS Downstream Channel Acquisition	Done
DOCSIS Ranging	Done
Establish IP Connectivity using DHCP	Done
Establish Time Of Day	Done
Transfer Operational Parameters through TFTP	Done
Register Connection	Done
Cable Modem Status	Operational
Initialize Baseline Privacy	Done

 

Cable Modem Operation	Value
Current Time and Date	Aug 08 2018 21:29:31
System Up Time	8 days 20h:53m:0s

 

[DirtyDan1337]

2 hours ago, Donut417 said:

If your using the Xfinity gateway in modem/router mode then probably not. As they dont support Mac address cloning. Your best bet is to look in the settings and find out how long the DHCP lease is for on your public IP, you need to make sure your modem is turned off and wait for the lease to expire. If your lucky you may get a new IP. Comcast assigns IP's based on the MAC address of what ever is connected to the modem. If your case your modem and router are one unit. 

 

For me, I own my own standard modem Non gateway bull shit.. If I were to change the router I had connected to my modem I would pull a new IP address from Comcast. 

Yeah, but I want to change that ip again.

[Arika]

why do you need to change your IP?

[Donut417]

1 hour ago, DirtyDan1337 said:

Yeah, but I want to change that ip again.

If your using their gateway then your screwed. Most ISP equipment doesn't support advance features. You can try giving them a call and see if they can do it. 

[DirtyDan1337]

7 hours ago, Donut417 said:

If your using their gateway then your screwed. Most ISP equipment doesn't support advance features. You can try giving them a call and see if they can do it. 

But i'm using it only as a modem and have a router connected to it. 

[Mikensan]

Just call comcast and ask for a DHCP release, say you're a victim of DOS attacks or something.

 

Some companies set leases for minutes / hours at a time, so how long you have to wait after unplugging your modem will vary. Majority of companies won't set it for 24 hours given the scarcity of IPv4 addresses, so you could just turn off your modem for 24 hours.

 

Easiest thing in my experience is just call your ISP.

[Donut417]

2 hours ago, DirtyDan1337 said:

But i'm using it only as a modem and have a router connected to it. 

Then use the mac address cloning feature on your router, assuming it has that feature. Set the mac address to another device on your network. That will pull a new IP address from Comcast. Or you can call them. Keep in mind that we ran out of IPv4 addresses years ago, so Comcast might not be able to change the address. 

 

1 hour ago, Mikensan said:

Majority of companies won't set it for 24 hours given the scarcity of IPv4 addresses, so you could just turn off your modem for 24 hours.

Hard to say. I know people you have had the same IP address on Comcast for a year. Ive also know people to get a new one daily. Comcast doesnt run all area's the same, so it really depends on how they run the area the OP is in. 

[Mikensan]

3 hours ago, Donut417 said:

Then use the mac address cloning feature on your router, assuming it has that feature. Set the mac address to another device on your network. That will pull a new IP address from Comcast. Or you can call them. Keep in mind that we ran out of IPv4 addresses years ago, so Comcast might not be able to change the address. 

 

Hard to say. I know people you have had the same IP address on Comcast for a year. Ive also know people to get a new one daily. Comcast doesnt run all area's the same, so it really depends on how they run the area the OP is in. 

If your device is online, when it renews it will keep the same IP address - much like on a normal network. It's rare that when you renew a lease you lose your IP, but if you reboot your modem just at the right time you could lose it - depending on the lease time.

 

The lease time definitely varies by location and company.

[AbsoluteFool]

22 hours ago, Donut417 said:

DHCP is a server that assigns IP address. Comcast does not do Static IP's  for residential customers. So YES, Comcast uses a DHCP server. And yes your router has a built in DHCP server for your home network. The picture below is to my modem, Not a modem/router, standard no bull shit cable modem. See the part about DHCP? Because Comcast has a DHCP server they use the assign Dynamic IP's to their customers. 

Cable Modem

Status	Signal	Addresses	Configuration	Logs	Open Source	Help

This page provides information about the startup process of the Cable Modem. If there is a problem with the startup, the word "Failed" may appear in the Status column. Should this occur, visit the Help area and perform the Checkup procedures listed there. If the problem continues, click on the word "Failed" for more detailed information about the failure, or call your service provider for assistance.

---

 

Task	Status
DOCSIS Downstream Channel Acquisition	Done
DOCSIS Ranging	Done
Establish IP Connectivity using DHCP	Done
Establish Time Of Day	Done
Transfer Operational Parameters through TFTP	Done
Register Connection	Done
Cable Modem Status	Operational
Initialize Baseline Privacy	Done

 

Cable Modem Operation	Value
Current Time and Date	Aug 08 2018 21:29:31
System Up Time	8 days 20h:53m:0s

 

Why are you putting in this? The DHCP server on the router can't change the public IP for him. His ISP have to do this. That list of things was just useless.

[Donut417]

42 minutes ago, AbsoluteFool said:

Why are you putting in this? The DHCP server on the router can't change the public IP for him. His ISP have to do this. That list of things was just useless.

Because the ISP has their OWN DHCP server that assigns IP addresses. SO YEAH thats what Im proving. Because my modem dont have a router built in because I dont use a shit ISP gateway. Secondly, if you have a setup like mine, you use the mac address cloning feature on the router, cloning lets say a PC on the network to make the router look like it has a different mac address then its own. Then you restart the modem, it detects a new mac address, to the system that means it has to issue a new IP address. BECAUSE the old one is attached to the old mac address. Get it now? Or do you need me to break it down further? So technically you dont have to call the ISP. Because I have been with Comcast for over a decade, they have so special ed people working for them. I doubt even half know what an IP address is. 

[AbsoluteFool]

14 hours ago, Donut417 said:

Because the ISP has their OWN DHCP server that assigns IP addresses. SO YEAH thats what Im proving. Because my modem dont have a router built in because I dont use a shit ISP gateway. Secondly, if you have a setup like mine, you use the mac address cloning feature on the router, cloning lets say a PC on the network to make the router look like it has a different mac address then its own. Then you restart the modem, it detects a new mac address, to the system that means it has to issue a new IP address. BECAUSE the old one is attached to the old mac address. Get it now? Or do you need me to break it down further? So technically you dont have to call the ISP. Because I have been with Comcast for over a decade, they have so special ed people working for them. I doubt even half know what an IP address is. 

The IP wont change that easily. The IP from your ISP have a TTL or instant EOL at time out. Changing the MAC address on the router has nothing to do with changing the IP provided by the ISP.

 

So again. Why are you talking about these DHCP things?

[Lurick]

9 minutes ago, AbsoluteFool said:

The IP wont change that easily. The IP from your ISP have a TTL or instant EOL at time out. Changing the MAC address on the router has nothing to do with changing the IP provided by the ISP.

 

So again. Why are you talking about these DHCP things?

Changing the WAN port's MAC address is how you change the dynamic IP address for most ISPs since the old IP is going to bound to the old MAC

[AbsoluteFool]

46 minutes ago, Lurick said:

Changing the WAN port's MAC address is how you change the dynamic IP address for most ISPs since the old IP is going to bound to the old MAC

If the IP was bound to the MAC address the ISP would sit with a bunch of IPs that are not in use. In other words changing the MAC address just brut forced the TTL.

The MAC address has nothing to do with how ISP assign ip addresses, Staticly or automatic.

[Lurick]

3 minutes ago, AbsoluteFool said:

If the IP was bound to the MAC address the ISP would sit with a bunch of IPs that are not in use. In other words changing the MAC address just brut forced the TTL.

The MAC address has nothing to do with how ISP assign ip addresses, Staticly or automatic.

That's not how it works. After a period of time those reservations will time out in their system if they are not refreshed when the DHCP timer reaches it's refresh point. The MAC address is how the reservation is bound in the ISP's system to the modem/router combo or to the router sitting behind a standalone modem, so it most definitely does have something to do with how an ISP assigns an IP address.

[AbsoluteFool]

1 minute ago, Lurick said:

That's not how it works. After a period of time those reservations will time out in their system if they are not refreshed when the DHCP timer reaches it's refresh point. The MAC address is how the reservation is bound in the ISP's system to the modem/router combo or to the router sitting behind a standalone modem, so it most definitely does have something to do with how an ISP assigns an IP address.

Yoiu know that made no sense what so ever? If the ISP bound the IP to every mac address that would cause huge internal problems. The MAC address belongs to each nic, when you change the MAC address the isp will think you are a new device and assign you an ip address. With other words you force the TTL (or DHCP timer) as you called it, to end.

[Lurick]

Just now, AbsoluteFool said:

Yoiu know that made no sense what so ever? If the ISP bound the IP to every mac address that would cause huge internal problems. The MAC address belongs to each nic, when you change the MAC address the isp will think you are a new device and assign you an ip address. With other words you force the TTL (or DHCP timer) as you called it, to end.

So you just demonstrated you have no clue how a MAC address works. A MAC address is layer 2 and does not traverse anything beyond the local link. That's why it's called link local. There is a SINGLE MAC address that's present to the ISP's servers for reservations and that's the MAC of the router connected to their node (modem, ONT, etc), or the system MAC in a combo unit. The only other MAC address that comes into play is the HFC MAC of the modem itself to allow it onto the network, if you have a DOCSIS provider.

[AbsoluteFool]

Just now, Lurick said:

So you just demonstrated you have no clue how a MAC address works. A MAC address is layer 2 and does not traverse anything beyond the local link. That's why it's called link local. There is a SINGLE MAC address that's present to the ISP's servers for reservations and that's the MAC of the router connected to their node (modem, ONT, etc), or the system MAC in a combo unit. The only other MAC address that comes into play is the HFC MAC of the modem itself to allow it onto the network, if you have a DOCSIS provider.

Before you talk about who doesen't know how anything works. Try to check your own facts. Each nic have a MAC address. That's how the internet works, you cannot use ethernet or any connection without it. If the ISP bound each IP to every MAC address on a device the IP would still be assigned to something that does not excist making internal problems for the ISP. The MAC address is a uniqe indentifier for the NIC. When you change the MAC address the isps DHCP server will act as this is a new device connecting assigning an ip to it. 

 

In other words, what you called "Timer" on the DHCP server (Learn the term btw: TTL or Time To Live) ends it will assign you a new IP, by changing the MAC address you force the TTL to end.

 

I suggest you do some reading in IPv4, MAC and DHCP. And stop being a big mouth, you make no sense what so ever. "Timer" lmfao

[Lurick]

1 minute ago, AbsoluteFool said:

Before you talk about who doesen't know how anything works. Try to check your own facts. Each nic have a MAC address. That's how the internet works, you cannot use ethernet or any connection without it. If the ISP bound each IP to every MAC address on a device the IP would still be assigned to something that does not excist making internal problems for the ISP. The MAC address is a uniqe indentifier for the NIC. When you change the MAC address the isps DHCP server will act as this is a new device connecting assigning an ip to it. 

 

In other words, what you called "Timer" on the DHCP server (Learn the term btw: TTL or Time To Live) ends it will assign you a new IP, by changing the MAC address you force the TTL to end.

 

I suggest you do some reading in IPv4, MAC and DHCP. And stop being a big mouth, you make no sense what so ever. "Timer" lmfao

You know what, you continue with your ignorance but I know all about how IPv4, MAC address, and DHCP works.

Each NIC, of course, has it's own MAC Address but you're trying to tell me that they traverse links, that's not how they work. When your computer sends a packet it has a source MAC of it's own and a destination MAC of the receiving device. That device then decaps the packet, removes the source mac of the machine and replaces it with it's own and forwards it on with a new destination MAC address. Therefor everything leaving your router going to the ISP's network has a single source MAC address, that of the router/modem/etc. connected to their equipment and the MAC address is used as a unique identifier to assign a lease to a customer.

 

TTL is Time to Live and how many hops a packet takes before it is discarded, this is to help prevent network loops at the IP layer, ie: why you can have a broadcast storm in a flat L2 network because TTL isn't used at Layer 2. DHCP uses a Lease Time to dictate how long a reservation is active, not TTL, and when the lease timer reaches half of the total lifetime the device is supposed to send a refresh request to the DHCP server to refresh the timer.

[Unhelpful]

6 minutes ago, AbsoluteFool said:

 

You seem to be extremely confused. Just let people more knowledgeable than you educate you, you clearly need it.

 

Your username is relevant.

[AbsoluteFool]

More educated? If he was so educated he would know the term or TTL on the lease time. When you break that connection the TTL ends instantly.

 

Ignorance. he know everything about how IPv4, MAC and DHCP works. But he don't know the right technical terms. 

In other words he can conntact his ISP and get some education from them. He seem impossible to reach.

[AbsoluteFool]

Here is some educational material for you https://en.wikipedia.org/wiki/MAC_address