How do I locate my IP address?

What IP address can reveal?

Hi, I'm looking for the best way to find out an IP address that I think I may have visited in the past.

The reason for this is that I can't access one of my companies web site anymore, and the IP address from the network log tells me it was the address that I used in the past to login to it. (I've changed the IP address of course). I've also not logged into it from a different computer recently.

So, if anyone has any good suggestions, they would be greatly appreciated. Thank you.

The IP address of a user (logged in or not) changes when he goes to another machine, even on the same subnet. I can't even think of a situation where it would stay constant for longer than the time needed for the DNS round-trip. If you really need a reliable address, get a new IP address for your computer and register a domain name (in case you want to use it again in future).

Yes, IPs don't change very often. But your router assigns them in a dynamic fashion, and there is always a small chance that your IP will change by the time your ISP's DNS server updates its tables. And your own DHCP server may assign a new IP to your computer, so the chance is still there.

This is a good point. I'll try and look into what would happen if I were to use a static IP address. I may try this for a while and then come back and post my findings.

Another thought I have is that if the server is still up and running, someone may have logged in. Maybe some other person did. Does a username have to be unique? I guess it doesn't have to be a unique IP, but a unique username? I'm going to try and research this more and then come back with my findings.

Yes, a valid username has to be unique (so it's usually a domain name, but there are some examples of a single IP address being used, though I haven't seen any in a long time), and the username has to be unique across all computers on the network (ie you don't want to reuse your username if you're logged in from two machines). And there are certainly services out there that would allow you to use your own username on their website without a domain name.

How can I detect an IP address?

I'm asking about this for an application that I'm building.

Is it possible for an application to detect IP addresses? If so, how could I do that? I am developing for Android 4.0 and above.

You can use the InetAddress class: InetAddress addr = InetAddress.getByName("192.168.2");
String ip = addr.getHostAddress(); As David points out: getByName(.) will find the first network interface with a DNS name equal to the argument. Note, though, that there's no guarantee that it's the address you asked for; on most of today's networks, several computers have the same IP address. I would suggest using getAddress() (or getByName() or getAllByName()). The problem with getAddress() is that it returns all addresses for the current system if you are a windows user. From the Android documentation.isUnresolved()) catch (UnknownHostException uhe) }
return InetAddress.getByAddress(localaddr.

How do I find out who owns an IP address?

I have a webserver, currently hosted in the Cloud with the company I work for.

It has been used by my company for the past year and a half, but now I am looking to move it to my personal server, and I need to find out who the owner of the IP address is. I have Googled around, and found nothing really definitive. Some sites say it's not possible, others say that it's possible, but I can't find a definitive answer that says what they are talking about.

What exactly is going on here? How can I get the details of who owns the IP address? Generally speaking, it depends on what network protocol you're using. You're going to want to do some research on netflow to figure out the information. You'll generally have to be logged into the web server in question.