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There's no particular reason for wanting to change my prefix for my local IP, I'm just wondering if it's possible.

So can I change my local IP from 192.168.x.x to something of my own choosing? I assume I'll have to edit some of the router settings.

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Which part? The x.x? Yes. The 192.168? No. –  Synetech Aug 29 '12 at 21:27
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(Of course it depends on your particular router.) –  Synetech Aug 29 '12 at 21:34
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@Synetech - You can of course change the 192.168 part. You just have to change the starting address. As Josh points out it could be 10.0.x.x or 172.16.x.x in addition to 192.168.x.x I suggest doing more research before you say something is not possible. Every router on the market lets you change this. –  Ramhound Aug 29 '12 at 21:39
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@Ramhound, I’m quite familiar with the other private address ranges, but you may want to show some examples because I have never seen a router support the other private address ranges by default (at least not without special third-party firmware like DD-WRT, OpenWRT, FreeWRT, Tomato…) That’s why I added it depends on your router. –  Synetech Aug 29 '12 at 21:46
    
No one has answered whether I can change it to something of my choosing and not predefined values. –  PriestVallon Aug 29 '12 at 22:44

3 Answers 3

up vote 2 down vote accepted

You can change your router's IP to whatever the router firmware will allow. I don't think the majority require you to stay within the 192.168.0.0/24 range as others have mentioned - some real cheap routers may behave this way. I believe most just insist that you enter a valid IP and netmask.

When you assign an IP address to the LAN-facing interface of a router, you are also usually deciding the subnet of your home network. So e.g. if you assign the LAN-facing interface of your router the IP address and netmask 10.0.0.1/255.255.0.0, you are usually implicitly saying every device on your LAN is going to have an IP address from 10.0.0.0 to 10.0.255.254 (with 10.0.255.255 being the broadcast address for your network). Just want to make the point that changing a router IP may potentially affect a lot more than your router.

I think it's important to mention that if you do not stay on the private ranges as others have mentioned, you risk having an address on your LAN that's the same as a host out on the external Internet, and may not be able to reach specific websites as a result.

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And with the running out of IPv4 addresses, the *risk of using an address that is the same as a host on the internet grows larger and larger. It's a bad idea, and 100% unnecessary. I understand the OP was asking theoretically, but it is worth mentioning. –  JoshP Aug 29 '12 at 23:41

There are three sets of address spaces for private networks (as in, not routed through the public internet) to use.

  • 192.168.0.0 - 192.168.255.255
  • 172.16.0.0 - 172.31.255.255
  • 10.0.0.0 - 10.255.255.255

If you are using a router firmware like DD-WRT, you can use one of these ranges by setting the router's IP address to be in that range (as in, make the routers address 10.0.0.1 or something like that).

I don't know if your average, out of the box home router will allow you to do this, however.

edit: I just checked my Verizon router at home and it also has an option to specify what IP range it gives out, so this option may be more common than I thought.

edit2: I just read your comment, you do not have to pick these ranges, but you would then be assigning your computers addresses that are available to public use. If you were to do this, you could have trouble connecting to any company that actually 'owns' that address range.

For example: in one of the comments, someone mentioned using Boeing'ss private address space. Suppose you picked the range 130.76.96.1-255. If one of the computers is assigned 130.76.96.107, you'd no longer be able to access Boeing's website (probably - it's possible a packet might make it out, but most likely it'd just time out or something).

In other words, if you don't own the IP address range, you probably shouldn't use it.

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+1 Your answer is much better because instead of simply mentioning the private address ranges, you specifically indicated that most routers don’t support other ones by default. –  Synetech Aug 29 '12 at 21:48
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I'm not sure "most" other routers don't support the other ranges. Might want to substantiate that. I've personally not run into to a router that didn't allow me to change it. For instance Apple's Airport comes with the 10 dot network set as the default, though they offer the others in a drop-down. –  JoshP Aug 29 '12 at 21:54
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You could use an address block not reserved for private networks, but the problem is that you will be unable to communicate with any actual Internet machines using those same addresses. I worked for a company once that randomly chose a block assigned to Boeing for its private network. Then it got a contract with Boeing. Strangely, Boeing's computers couldn't talk to theirs. Ooops. –  David Schwartz Aug 29 '12 at 21:57
    
@Josh, AirPort may support it, but what about the 1000’s of other, non-Apple routers? When I say most routers don’t “support” other ranges, I don’t mean they don’t let you enter it (though it’s possible; my DI-524 won’t let me enter a netmask ending in 252), but even if you can set the IP to something else, that doesn’t mean that all of the myriad functions like firewall, NAT, DHCP, etc. will necessarily work because the software may assume a 192.168 prefix (of course if it then allows arbitrary IPs, that’s that’s poor design). At the very least, you’d have to change all of the rules with IPs. –  Synetech Aug 30 '12 at 15:17
    
@Synetech, How about the Linksys WRT54G. That has got to be one of the most ubiquitous consumer routers out there. It also has the option. It's default is the class C (as all linksys routers are), but you can alter any of the 4 octets that define its own IP. As it happens, only class C subnets are allowed, but any network definition would work. In any case, we can debate the good/bad design choices, the ease of use, the myriad settings that follow, but none of that changes the answer to the OP question of whether or not it's possible to change your local IP to something other than 192. –  JoshP Aug 30 '12 at 20:09

There are three private IP blocks commonly used for LAN addressing

  • Class A - 10.0.0.0 - 10.255.255.255
  • Class B - 172.16.0.0 - 172.31.255.255
  • Class C - 192.168.0.0 - 192.168.255.255

Check out the widipedia entry for Private Network

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I use 10.0.0.x. So much easier and quicker to write than 192.168.x.x. –  Kent Aug 29 '12 at 21:35
    
> There are three private IP blocks commonly used for LAN addressing Yes, but most consumer routers don't support 10 or 172 by default. –  Synetech Aug 29 '12 at 21:49

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