Helping people with computers... one answer at a time.

A computer's IP (Internet Protocol) address identifies it on a TCP/IP network. There's a lot of concern about what can or cannot be determined from an IP address, or even how to find an IP address. IP addresses are a critical component of network data transfer.

Am I stealing someone else's IP address by resetting my router?

Resetting a router can cause it to revert to its default. If you'd been using a static IP it may revert to dyanmic configuration, but is that theft?

Can I keep my IP address from changing when I switch out my router?

IP addresses can seem confusing; email headers have them, routers have them, web pages have them... how do you sort it all out?

Can I set up my own static IP address for my internet connection?

Your IP address is set by your internet provider so that they can identify your computer and send you information from the internet. Changing it to set up a static IP address may not have the result that you expect.

Can I use my IP address to connect to my computer without remote desktop?

Remote Desktop is configured to keep your home computer secure while you connect to it from a remote machine. Doing this correctly requires the right software and permissions.

Can I use my router's DMZ to attach my IP-based phone to the internet?

On a NAT router any unrequested outside connection is blocked. Using the DMZ is a good workaround.

Does email coming from the same IP address imply that it was the same computer?

IP addresses are encoded into email headers. But if you get two emails from the same IP address you can't assume that they came from the same computer.

How do I determine my IP address in Windows Vista?

Determining your IP address is easy, but we first have to ask: which IP address do you want? I'll look at determining both.

How do I determine the subnet mask I'm supposed to use?

A subnet mask is one part of the information used to make a network connection. For most people, it's something you need never know about.

How do I find out who's at a particular IP address?

Internet users often want to identify who someone else might be with only an IP address to go on. It's just not something you and I can do.

How do I find the DNS server being used by my PC?

The DNS servers used on your computer are most likely specified by your ISP. I'll look at how to tell what they are and how to change them.

How do I get a new IP address?

Getting a new IP address on the internet can be difficult. The real issue is that a new IP address may not solve the problem you're facing.

How do I stop my neighbor from using my IP address?

If it's certain that a neighbor is using your IP address without permission, you need to take steps. But first, you need to make sure.

How do I stop someone from using or voting from my IP address?

Many online polls and voting tools use your IP address to keep track of the number of votes you've made. Unfortunately that technique is flawed.

How do I translate a URL to an IP address?

Mapping a domain to an IP address is very easy with several tools, both on your machine and on the internet. I'll look at the two I use.

How to find the IP address of my computer?

Determining your own IP address is very easy, but it first requires understanding which IP address it is you want to see.

Is DHCP safe?

DHCP is a fundamental technology to assign IP addresses to computers connected to a network. There are scenarios where DHCP might be spoofed.

Is dial-up safer?

When you dial-up to get an internet connection you typically get a different IP address each time. Is that safer or more anonymous? Not really.

Is it normal for an IP address to change from time to time?

If you connect to the internet as most users do your machine will be assigned a dynamic IP address that can change without notice, or any real effect.

Is it possible to hack an IP address?

You cannot hack an IP address, as it's fundamental to routing data on the internet. However, there are scenarios where IP addresses can appear the same.

My work and home computers have the same IP address, how do I fix that?

Conventional wisdom says two computers can't have the same IP address. Technically true but incomplete. The same IP can be used on different networks.

Should I use Google's new DNS services?

Google has begun offering DNS services. I'll look at what that is, why that is, and whether or not it's worth your looking into.

What IP address do I put in my browser to secure my router?

To connect to your router, you first find your gateway address and type that into the address bar of a browser window: I explain how.

What happens if two computers have the same IP address?

Two computers should never have the same IP address if they're on the same network. If they do, results are unpredictable.

What is a "subnet mask"?

A subnet mask is a way of telling your computer or router what network addresses it can consider local and which are remote.

When is a dynamic IP address assigned?

It happens at some part of the boot process. It's independent of when you login. It's just that sometimes it takes a little longer than others.

Why doesn't accessing a site by its IP address work?

It's not uncommon for tens, if not hundreds of websites to be located on a single web server. When that happens, an IP address just isn't enough.

Why is my IP blocked at a website I visit regularly after I changed ISPs?

IP address blocking frequently has an unintended side-effect: you could end up paying for someone else's bad behavior.

Why is my dropdown of websites suddenly gone and Facebook telling me I have a new IP address?

Websites can be cleaned from your drop-down menus and IP addresses can change. That in itself is not indicative of a hack. A few steps will increase security.

Will IPv6 break my internet on old machines?

Recent news reports about the transition to IPv6 have many people concerned. For the average consumer, I believe there's little if any immediate impact.