Changing my IP Address
 

I called AT&T tech support about changing my IP Address, their final answer was to use ipconfig /release which of course doesn't work on OS X.

I googled around, and the command I found to be similar was "if config en0 down" and then up, but for some reason I'm getting a Permission Denied error when I enter that into Terminal. I called Apple support and their first answer was hook it up, so I hooked up my Macbook to my Uverse modem/router via ethernet. Same problem. I called again and then they wanted $50 to even talk to me, so here I am!

Any ideas?

Your ip address is supplied by your isp, unless you're using a router. Even then, the router's ip address (your WAN address) is still provided by your isp. Why do you want to change it?

And further to CWT's comment, my cable ISP always gives back the same number if I renew. They only change it when they alter the network or insert new routers.

I think I'm going to have to unplug my modem/router combo for a day or something so that when I connect it will hook me up to a new public address. It's odd that my connection is supposedly dynamic but my public IP address seems to stay the same for months at a time if not years.

It's actually fairly normal. There's no need to give you a new address unless somebody else grabs yours, and most of the time it doesn't matter anyway. Of course, if you start depending on a dynamic address remaining static (say for a web server) then Murphy's Law will apply. ;)

Mine averages about 9 months between changes and the last time I had the modem off, it came back with the same IP Address anyway. I use dynDNS to keep track of it from away though because I never know for sure and I like to use my domain name to get at my home machine from away.

'dynamic' doesn't mean "always changing". It means "changes at the whim of the service provider". If they don't want to change it, then it doesn't.

Well I understand guys, but I'm trying to make them do this for me but it's not working. Same thing with renewing DHCP Lease. I'm at a loss here.

I don't think renewing the DHCP lease is supposed to change the address. The lease is a span of time, isn't it? It just reset the timer, that's how I thought it worked. I've used that button at public wireless hotspots and it rarely changes the address.

I should point out that apparently in Windows it's as simple as typing ipconfig /release and then ipconfig /renew into the command prompt. Should I just install a quick and dirty copy of Windows to do this? I'd like to be able to change my IP address at a whim to avoid download limits at sites etc...

"renew DHCP address" should start the address negotiation process fresh, but still doesn't guarantee you get a different IP address.

No need to run windows either. ipconfig /release --- /renew doesn't guarantee a new IP address; that's up to the DHCP server which may well just return the same address. If your ISP has upload download limits, for example, they are very reluctant to change IP addresses and then propagate that into their records of your activity.

Well how do I go about getting them to change it? The entry level support person didn't understand the concept of an IP address last time, and I'm not holding my breath for more.

Why exactly are you trying to change it?

DHCP, by nature, the client will always request another lease for the same IP it was using. Furthermore, if your ISP has IPs chopped up in virtual LANs, they very well could have just assigned you a block of IPs which is why you are always getting the same WAN IP over and over again.

When you change the IP on the client side by renewing DHCP, that does not affect the WAN IP at all. That only refreshes the LAN IP, even in Windows the nature is the same as networking is a standard and no different between platforms.

You are behind some sort of router as a 192.168.x.x IP is a private IP address, and non rout-able, unless of course in use with a router.

The fact is, that your ISP's tier 1 and even tier 2 tech support may not even have access to the proper networking hardware/equipment to even change your IP address.

So, I really have to ask, what is the higher goal of changing your IP?

As I said, I'd like to be able to change my public IP Address to avoid download limits on sites like megaupload etc... it may seem trivial, but that's my motive. I was lead to believe that changing your IP address was fairly simple. The curiosity for me is that the equivalent command in Terminal is giving me an "Access denied" even when I'm hooked up via ethernet, which leads me to believe It's not that I'm coming back online and being given the same IP address, it's not going that far (Access denied would mean that the command didn't execute, right?)

1) For some commands (those that change system parameters for example), you need to preface the command with 'sudo' so that the command executes with 'root' privileges.

2) Running commands on your Mac will only affect your Mac's IP address. If your Mac is behind a router (as it seems), then your Mac's IP address is only relevant inside your local network. It is the IP address of your router that is seen by the wider Internet.

3) As others have said, the IP address of your router is (usually) assigned by your ISP. And even though you have a "dynamic" IP address, that only means that it might change (whenever the ISP feels like it), not that it will change. ISPs often keep you at the same IP address for long times. It is unlikely you will be able to convince the ISP to make your IP address change - unless you are willing to pay them something for their trouble.

Thank you for that layman explanation hayne, I very much appreciate it. Do I have any recourse for finding out how long the lease is for my current IP address on my router? You can consider this topic resolved, I learned what I needed to. Thanks!

Even if you find out what your lease is (my router lists this right next to the IP information and includes buttons for releasing and renewing), releasing that IP or waiting for the lease to expire does not guarantee that you'll receive a new IP. That is up to your ISP's hardware.

The reason you're getting "Access Denied" is because "ifconfig en0 down" and ifconfig en0 up" require administrator privileges. Use "sudo ifconfig" instead. Note, that it's "ifconfig" not "if config" as you had in your initial post.

Your best solution is to connect over a dial-up connection, which pretty much guarantees you'll receive a new IP on each reconnect. This of course defeats your goal of downloading faster from file sharing sites.

Your alternatives are:
Buy access to your file sharing sites. This has the benefit of not circumventing the Terms of Use of the site and probably allowing simultaneous downloads as well.
Use Tor to access the site. This has the downside of being slower and bumping up against other users that are trying to do the same thing. If, that is, the site doesn't outright block access from Tor.

a way i've found which sometimes changes my IP, is to connect with another device, i.e with a different MAC address (Media Access Control address)...

i noticed my IP would stay the same for months, then my router broke and i connected a new one, bingo, new IP

if you have your router connected, switch everything off and disconnect the router, connect your computer directly to the modem and switch everything back on

another way could be to change the MAC address of the router, some routers allow you to do this...

fracai is correct though, best to buy access

Just turn your dsl router or modem off for a few hrs and back on. you should have a new IP