get IP address from computer

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1.00/5 (2 votes)

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Hot to get the right IP address? I have tied this:

C#

string strHostName = System.Net.Dns.GetHostName();
IPHostEntry ipEntry = System.Net.Dns.GetHostEntry(strHostName);
IPAddress[] addr = ipEntry.AddressList;
for (int i = 0; i < addr.Length; i++)
{
MessageBox.Show("IP Address {0}: {1} " + addr[i].ToString());
}

but it shows me all the numbers that are not the IP. I only need to show the right one.

Posted 11-Apr-13 5:44am

Member 4347041

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[no name] 11-Apr-13 11:46am

What are the numbers that it is showing you? What would be the "right" one?

Sergey Alexandrovich Kryukov 11-Apr-13 11:48am

AddressList really gives an array of IP addresses. This is correct result. No one it more "right" than another. :-)
—SA

[no name] 11-Apr-13 13:55pm

What does that have to do with anything? Look again at his message box string. Do you really think that that would display an IP address as he wants?

Sergey Alexandrovich Kryukov 11-Apr-13 15:17pm

Oh, no! :-)
—SA

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OriginalGriff · Answer 1 · 2013-04-11T05:58:00

Solution 2

If you mean "It gives me an IP address which is in the range '192.x.x.x' and does not match the number WhatsMyIP.com tells me" then it's not that simple.

The WhatsMyIP.com number is your internet address, which is actually the internet IP address of your router - it does not go any further than that. On the PC side of the router, you use different IP addresses assigned by your DHCP server (normally the router again) and which are normally in the range 192.172.x.x. Your PC never needs to know the internet IP address as the messgaes are all routed (and the IP addresses changed) by the router when it feeds your requests to the internet and returns the results.

If you want the actual internet IP address, then you either have to query the router directly (and all manufacturers give this differently, so I don't recommend it) or use an IP service on teh internet to find it - such as WhatsMyIP.com.

Posted 11-Apr-13 5:58am

OriginalGriff

Comments

Member 4347041 11-Apr-13 12:19pm

It shows me 4 of them, only one looks like IP, three of them are like this:
dr44::a7e2:7f7i:6f32:716g%19
And now i need the code to only look for that one that is IP, like 192.x.x.x

OriginalGriff 11-Apr-13 12:34pm

Ah! The others are IPV6 addresses, rather than the older IPV4 address you are used to. They are all IP addresses, but if you are really looking for your internal network IPV4 address, then add the following:
if (addr[i].AddressFamily == AddressFamily.InterNetwork)
{
MessageBox.Show(string.Format("Bingo!\n{0}:{1}", i, addr[i]));
}

Member 4347041 12-Apr-13 4:13am

Where is AddressFamily defined?

OriginalGriff 12-Apr-13 4:23am

System.Net.Sockets
http://msdn.microsoft.com/en-us/library/system.net.sockets.addressfamily.aspx

If you aren't sure where something is defined, put your cursor in the underlined name in VS, and a small blue line will appear at the beginning.
Put your mouse over the line, and a drop down will appear. Open the drop down, and it will give you options to add the namespace info by generating the using statement for you, or explicitly adding the namespace to the single line use. Handy!

Member 4347041 12-Apr-13 4:38am

Thanks. Where can i find all (list of) those libraries (using) and what their are containing?

OriginalGriff 12-Apr-13 4:47am

I know of no "one list" containing everything - there is just way, way too much to make it useful.
Google and MSDN generally find the class info if you look though, and that cross references to the assembly and namespace.

As for "what is available" that's really down to finding a book or course on the appropriate part of .NET - even just the networking stuff needs a whole book to cover it (as does LINQ, as does cryptography, etc.)

Member 4347041 12-Apr-13 12:42pm

Thanks. One more thing: the IP address that I get from this code (above) is totally different from IP address that I see in my gmail account or if I check it on the website. Why is that?
How to get the real one?

OriginalGriff 12-Apr-13 14:01pm

See my original answer! :laugh:
The IP you see there is the IP address of your router (or other internet connection device), not your PC - it doesn't pass through, and your PC IP doesn't pass out. All the PCs that connect to the internet via the same router have the same IP: which is one of the reasons that IP banning is not used more often - you can ban a whole company based on a single individual.

Member 4347041 12-Apr-13 15:01pm

Ok, now, is it possible to get the IP address of a router? I need it to pin-point the location of a user.

OriginalGriff 12-Apr-13 15:10pm

Only by communicating with it from outside the router-controlled area: i.e. the internet.
The IP address you want only exists on the internet side - to read it internally you either have to have the PC "call home" to somewhere outside, or look at it when it logs in to your website (then you get the Router IP automatically)

The only other way is to ask teh router itself, but as I said, all manufacturers present this info differently, so it's not a good general solution.

Member 4347041 12-Apr-13 15:43pm

The thing is that i wrote a program and when user saves files, program sends me an email. So i get the real number of made projects,... And i was thinking if i could get the IP address so i can see where the particular user is using the program. I thought that i get the IP with my code above but i can not use that IP. Is there another way to accomplish this? I need to get the location of a user.

OriginalGriff 13-Apr-13 2:54am

There are a couple of problems with that - the main one being that you will almost certainly need to have the client's email address and email password in order to send the email. Which means it may stop working in organisations which enforce a strict password change regime, assuming the user is willing to give you his password in the first place - I certainly wouldn't.

Why not set up a small web service and send the data direct to that? That will get the IP automatically, as well as any other info you need, and as long as the user has an open internet connection it will work fine.

Be aware though, that many users will see this as "snooping" and unless you can show a pretty good reason to do it will not be particularly amused to find out you are doing it - they may have concerns that the security of their saved data is compromised. I personally would not be over happy with this - some of my clients are very security conscious, and might stop using my services if they found out.

Member 4347041 13-Apr-13 5:58am

Sorry i was not clear: i have set up one email for all users (it`s hidden in code), when they save, program logs on that particular email (in the background), inserts password, ads text, attachments,...(sends email via stmp), and it works like you would send email to your self. So there is no need for your email, password,... the only thing i need is the right IP, so i can get the location. In "About" section in program is written that if you want to use the program you have to agree with terms of use, and so on. I am making a statistical data,... and i need to see in which states, cities,... is program more used that in other states, cities,...

OriginalGriff 13-Apr-13 6:21am

Provided you are on the same email server as the clients, it shouldn't be a problem - but if you install the app outside your LAN it probably won't work (the local email server will not recognise your username and password combo). And if it's inside your LAN, then why do you need the internet IP? :laugh:

Seriously - I'd look at a web service instead, it'd probably be easier and save the hassle of an email at all. You could store it direct into an DB instead, with the IP and geolocation results.

Member 4347041 13-Apr-13 6:43am

Now i am thinking of webrequest from google.com and to get the IP. Have you got a sample of code?

OriginalGriff 13-Apr-13 6:53am

Not sure where I got it from (It was a looooong time ago):
public string GetPublicIP()
{
String direction = "";
WebRequest request = WebRequest.Create("http://checkip.dyndns.org/");
using (WebResponse response = request.GetResponse())
using (StreamReader stream = new StreamReader(response.GetResponseStream()))
{
direction = stream.ReadToEnd();
}

//Search for the ip in the html
int first = direction.IndexOf("Address: ") + 9;
int last = direction.LastIndexOf("</body>");
direction = direction.Substring(first, last - first);

return direction;
}

Member 4347041 13-Apr-13 7:17am

Thanks. But what if this site changes? Is it possible to get from google.com?

OriginalGriff 13-Apr-13 7:23am

You're worried about site changes so you *want* to use google? :laugh:
I've never tried - I don't know if they have any web interface that provides it other than issuing a search for "whats my IP" but the changes of that remaining the same are about the same as adobe not updating their products...

These are reasons why I would create a basic web service - it's under your control!