I have a C# script that finds URLs and checks each one to see if it is valid. To be valid, it must have an IP address which means it will return info if queried in a nslookup. Not all valid URLs have a webpage, but they will have an IP address. That being the case, test for a website will not work. I searched for solutions but did not find a simple one.
My current method does a system call to nslookup and places it into a List. Then I loop through the list and check for "Non-existent domain". This works but I prefer not to use system calls if a C# alternative is available.
I can use HtmlAgilityPack and do a call to "https://www.whois.com/whois/" but some foreign URLs are not listed there and it seems like a lot of overhead for this kind of search.
I've tried the following System.Net method but no matter what URL I use, it fails.
string validURL = "a good URL";
try {
Uri myUri = new Uri(validURL);
var ip = Dns.GetHostAddresses(myUri.Host)[0];
Console.WriteLine("Found it");
} catch {
Console.WriteLine("Failed");
}
What is a good low cost method to determine if a URL is valid or fails?
Got it figured out. Pretty simple.
string validURL = "any url or ip adddress";
try {
IPHostEntry hostEntry = Dns.GetHostEntry(validURL);
}
catch {
Console.WriteLine("Failed");
}
If I have a need for the Host name and IP addresses it's done with just a few extra lines of code in the try section.
We are using maxmind geo ip location service in our web application. Utilizing this maxmind we need ipaddress to give as input.
We are following below snippet to get Ip address.
var ip = Request.UserHostAddress;
if (Request.Headers["X-Forwarded-For"] != null)
{
ip = Request.Headers["X-Forwarded-For"];
Console.WriteLine(ip + "|X-Forwarded-For");
}
else if (Request.Headers["REMOTE_ADDR"] != null)
{
ip = Request.Headers["REMOTE_ADDR"];
Console.WriteLine(ip + "|REMOTE_ADDR");
}
We are under corprate network, So in local environment as well as development environment we are used to get private ip address like this 10.X.X.X.
Using this address we always fails to locate the client location.
So real problem is when you passing external/public ip(190.X.X.X) to maxmind then only its working.
Do we really need to get external/public ips to give input to maxmind services.
You are using Maxmind for IP services that has everything to do with your clients' IP, not yours.
who are you trying to Geolocate?
For fraud services, who are you trying to evaluate?
Private IPs are used extensively by internal networks (home and corporations/enterprises..like yours), so they are not unique (aside from being non-routable on the public internet, etc.)
All geolocation providers work only on the public IP addresses. Private IP addresses are being used in LAN and can be re-issued again as long as it is not within the same LAN. There is no uniqueness to determine the geolocation information.
You are correctly using 10.xx.xx.xx range which is is reserved for private (internal) use.
All you need do is alter your code so that prior to your Maxmind look-up you replace the "10" IP to be looked-up with a "public" one for the same locale. If your company has multiple locations then you can create an array/table of internal IPs to public "locale identifying" IPs.
e.g. if the department in LA, USA uses 10.222.xx.xx; and NY,USA uses 10.123.xx.xx addresses then for these IPs simply Maxmind Lookup with an "equivalent" public IP. so for 10.123.xx.xx (NY, USA) look up 154.16.85.37 instead.
You may not even need to use Maxmind at all for your "10 IPs". E.g. if you simply need country code; then include it in your own "IP 10" look-up table/array and for IPs prefixed 10 instead of Maxmind look-up look-up from your own table.
I need to get an IP address for a given hostname from a DnsEndPoint, and convert it to an IPEndPoint. How would I go about doing this? WP7 lacks a Dns.GetHostEntry function, so is there any way to do this without creating a Socket, sending data to the host, then receiving a ping from the host and reading the RemoteEndPoint property to get the IP address of the host?
Try using DeviceNetworkInformation.ResolveHostNameAsync in the Microsoft.Phone.Net.NetworkInformation namespace, like this:
public void DnsLookup(string hostname)
{
var endpoint = new DnsEndPoint(hostname, 0);
DeviceNetworkInformation.ResolveHostNameAsync(endpoint, OnNameResolved, null);
}
private void OnNameResolved(NameResolutionResult result)
{
IPEndPoint[] endpoints = result.IPEndPoints;
// Do something with your endpoints
}
There is no way to do this built into the framework. You could use a socket assumming that the host supports ping. It will depend on the network you are running in (I'd assume you can't control this) and the exact requirements of the application.
It may be easier to get your app to work with IP addresses and not require a hostname if all you have is an IP address.
I think Im dealing with the same problem. I also have a dynamic IP updating the dns with No-ip.
For what I know the System.Net.Dns is not available in this version of Windows Phone.
Maybe in next releases.
http://msdn.microsoft.com/en-us/library/system.net.dns.aspx
At the start of my app Im going to create a web service call to the host (to the webserver in it) asking for the IPAddress. I think I'll solve the problem in the meantime.
This could be the WCF service
[ServiceContract]
public interface IService1
{
[OperationContract]
string GetIpAddress(string value);
}
public class Service1 : IService1
{
public string GetIpAddress()
{
// Add the proper error handling and collection matching of course
IPAddress s = Dns.GetHostAddresses("www.mysite.com")[0];
return s.ToString();
}
}
If you guys find a direct approach please let me know
Hi all, I seem to have found a discrepancy when testing ASP.NET applications locally on the built-in web server with Visual Studio 2008 (Cassini).
I've set up a host on my local machine associating dev.testhost.com with 127.0.0.1, since I have an application that needs to change its appearance depending on the host header used to call it.
However, when I request my test application using http://dev.testhost.com:1234/index.aspx, the value of Request.Url.Host is always "localhost". Whereas the value of Request.Headers["host"] is "dev.testhost.com:1234" (as I would expect them both to be).
I'm NOT concerned that the second value includes the port number, but I am mighty confused as to why the HOST NAMES are completely different! Does anyone know if this is a known issue, or by design? Or am I being an idiot?!
I'd rather use Request.Url.Host, since that avoids having to strip out the port number when testing... - Removed due to possibly causing confusion! - Sam
Request.Headers["host"] is the value received from the application that connects to the server, while the other value is the one the server gets when it tries to get the domain name.
The browser uses in the request the domain name entered because that is used in the case of virtual domains. The server reports the one set in the server preferences, or the first one it finds.
EDIT: Looking at the code of Cassini to see if it uses some particular settings, I noticed the following code:
public string RootUrl {
get {
if (_port != 80) {
return "http://localhost:" + _port + _virtualPath;
}
else {
return "http://localhost" + _virtualPath;
}
}
}
//
// Socket listening
//
public void Start() {
try {
_socket = CreateSocketBindAndListen(AddressFamily.InterNetwork, IPAddress.Loopback, _port);
}
catch {
_socket = CreateSocketBindAndListen(AddressFamily.InterNetworkV6, IPAddress.IPv6Loopback, _port);
}
// …
}
The explanation seems to be that Cassini makes explicit reference to localhost, and doesn't try to make a reverse DNS lookup. Differently, it would not use return "http://localhost" + _virtualPath;.
The Request.Headers["host"] is the host as specified in the http header from the browser. (e.g. this is what you'd see if you examined the traffic with Fiddler or HttpWatch)
However, ASP.NET loasds this (and other request info) into a System.Uri instance, which parses the request string into its constituent parts. In this case, "Host" refers to literally the host machine part of the original request (e.g. with the tcp port being in the Port) property.
This System.Uri class is a very useful helper class that takes all the pain out of splitting your request into it's parts, whereas the "Host:" (and for that matter the "GET") from the http header are just raw request data.
Although they both have the same name, they are not meant to be the same thing.
It's a matter of what the w3 specs say versus what the Microsoft Uri.Host property is supposed to contain. The naming does not imply an attempt by MS to provide identical functionality. The function that does include port numbers is Uri.Authority.
With the update you posted, you're still facing the same problem, just examining a different aspect of it. The Uri.Host property is not explicity or implicity stated to perform the same function as the headers that are defined in the w3 specs. In long form, here are some quotes from the Uri.Host MSDN page:
Uri.Host Property
Gets the host component of this instance.
Property Value
Type: System.String
A String that contains the host name. This is usually the DNS host name or IP address of the server.
There's no guarantee that this will match what is in the headers, just that it represents the host name in some form.
I need to find out the external IP of the computer a C# application is running on.
In the application I have a connection (via .NET remoting) to a server. Is there a good way to get the address of the client on the server side?
(I have edited the question, to be a little more clear. I'm apologize to all kind people who did their best to respond to the question, when I perhaps was a little too vague)
Solution:
I found a way that worked great for me. By implementing a custom IServerChannelSinkProvider and IServerChannelSink where I have access to CommonTransportKeys.IPAddress, it's easy to add the client ip on the CallContext.
public ServerProcessing ProcessMessage(IServerChannelSinkStack sinkStack,
IMessage requestmessage, ITransportHeaders requestHeaders,
System.IO.Stream requestStream, out IMessage responseMessage,
out ITransportHeaders responseHeaders, out System.IO.Stream responseStream)
{
try
{
// Get the IP address and add it to the call context.
IPAddress ipAddr = (IPAddress)requestHeaders[CommonTransportKeys.IPAddress];
CallContext.SetData("ClientIP", ipAddr);
}
catch (Exception)
{
}
sinkStack.Push(this, null);
ServerProcessing srvProc = _NextSink.ProcessMessage(sinkStack, requestmessage, requestHeaders,
requestStream, out responseMessage, out responseHeaders, out responseStream);
return srvProc;
}
And then later (when I get a request from a client) just get the IP from the CallContext like this.
public string GetClientIP()
{
// Get the client IP from the call context.
object data = CallContext.GetData("ClientIP");
// If the data is null or not a string, then return an empty string.
if (data == null || !(data is IPAddress))
return string.Empty;
// Return the data as a string.
return ((IPAddress)data).ToString();
}
I can now send the IP back to the client.
This is one of those questions where you have to look deeper and maybe rethink the original problem; in this case, "Why do you need an external IP address?"
The issue is that the computer may not have an external IP address. For example, my laptop has an internal IP address (192.168.x.y) assigned by the router. The router itself has an internal IP address, but its "external" IP address is also internal. It's only used to communicate with the DSL modem, which actually has the external, internet-facing IP address.
So the real question becomes, "How do I get the Internet-facing IP address of a device 2 hops away?" And the answer is generally, you don't; at least not without using a service such as whatismyip.com that you have already dismissed, or doing a really massive hack involving hardcoding the DSL modem password into your application and querying the DSL modem and screen-scraping the admin page (and God help you if the modem is ever replaced).
EDIT: Now to apply this towards the refactored question, "How do I get the IP address of my client from a server .NET component?" Like whatismyip.com, the best the server will be able to do is give you the IP address of your internet-facing device, which is unlikely to be the actual IP address of the computer running the application. Going back to my laptop, if my Internet-facing IP was 75.75.75.75 and the LAN IP was 192.168.0.112, the server would only be able to see the 75.75.75.75 IP address. That will get it as far as my DSL modem. If your server wanted to make a separate connection back to my laptop, I would first need to configure the DSL modem and any routers inbetween it and my laptop to recognize incoming connections from your server and route them appropriately. There's a few ways to do this, but it's outside the scope of this topic.
If you are in fact trying to make a connection out from the server back to the client, rethink your design because you are delving into WTF territory (or at least, making your application that much harder to deploy).
Dns.GetHostEntry(Dns.GetHostName()); will return an array of IP addresses. The first one should be the external IP, the rest will be the ones behind NAT.
So:
IPHostEntry IPHost = Dns.GetHostEntry(Dns.GetHostName());
string externalIP = IPHost.AddressList[0].ToString();
EDIT:
There are reports that this does not work for some people. It does for me, but perhaps depending on your network configuration, it may not work.
I found a way that worked great for me. By implementing a custom IServerChannelSinkProvider and IServerChannelSink where I have access to CommonTransportKeys.IPAddress, it's easy to add the client ip on the CallContext.
public ServerProcessing ProcessMessage(IServerChannelSinkStack sinkStack,
IMessage requestmessage, ITransportHeaders requestHeaders,
System.IO.Stream requestStream, out IMessage responseMessage,
out ITransportHeaders responseHeaders, out System.IO.Stream responseStream)
{
try
{
// Get the IP address and add it to the call context.
IPAddress ipAddr = (IPAddress)requestHeaders[CommonTransportKeys.IPAddress];
CallContext.SetData("ClientIP", ipAddr);
}
catch (Exception)
{
}
sinkStack.Push(this, null);
ServerProcessing srvProc = _NextSink.ProcessMessage(sinkStack, requestmessage, requestHeaders,
requestStream, out responseMessage, out responseHeaders, out responseStream);
return srvProc;
}
And then later (when I get a request from a client) just get the IP from the CallContext like this.
public string GetClientIP()
{
// Get the client IP from the call context.
object data = CallContext.GetData("ClientIP");
// If the data is null or not a string, then return an empty string.
if (data == null || !(data is IPAddress))
return string.Empty;
// Return the data as a string.
return ((IPAddress)data).ToString();
}
I can now send the IP back to the client.
Better to just use http://www.whatismyip.com/automation/n09230945.asp it only outputs the IP just for the automated lookups.If you want something that does not rely on someone else put up your own page http://www.unkwndesign.com/ip.php is just a quick script:
<?php
echo 'Your Public IP is: ' . $_SERVER['REMOTE_ADDR'];
?>
The only downside here is that it will only retrieve the external IP of the interface that was used to create the request.
Jonathan Holland's answer is fundamentally correct, but it's worth adding that the API calls behind Dns.GetHostByName are fairly time consuming and it's a good idea to cache the results so that the code only has to be called once.
The main issue is the public IP address is not necessarily correlated to the local computer running the application. It is translated from the internal network through the firewall. To truly obtain the public IP without interrogating the local network is to make a request to an internet page and return the result. If you do not want to use a publicly available WhatIsMyIP.com type site you can easily create one and host it yourself - preferably as a webservice so you can make a simple soap compliant call to it from within your application. You wouldn't necessarily do a screen capture as much as a behind the scenes post and read the response.
If you just want the IP that's bound to the adapter, you can use WMI and the Win32_NetworkAdapterConfiguration class.
http://msdn.microsoft.com/en-us/library/aa394217(VS.85).aspx
Patrik's solution works for me!
I made one important change. In process message I set the CallContext using this code:
// try to set the call context
LogicalCallContext lcc = (LogicalCallContext)requestMessage.Properties["__CallContext"];
if (lcc != null)
{
lcc.SetData("ClientIP", ipAddr);
}
This places the ip address in the correct CallContext, so it can later be retrieved with
GetClientIP().
Well, assuming you have a System.Net.Sockets.TcpClient connected to your client, you can (on the server) use client.Client.RemoteEndPoint. This will give you a System.Net.EndPoint pointing to the client; that should contain an instance of the System.Net.IPEndPoint subclass, though I'm not sure about the conditions for that. After casting to that, you can check it's Address property to get the client's address.
In short, we have
using (System.Net.Sockets.TcpClient client = whatever) {
System.Net.EndPoint ep = client.Client.RemoteEndPoint;
System.Net.IPEndPoint ip = (System.Net.IPEndPoint)ep;
DoSomethingWith(ip.Address);
}
Good luck.
I believe theoretically you are unable to do such a thing while being behind a router (e.g. using invalid ip ranges) without using an external "help".
You can basically parse the page returned by doing a WebRequest of http://whatismyipaddress.com
http://www.dreamincode.net/forums/showtopic24692.htm
The most reliable manner of doing this is checking a site like http://checkip.dyndns.org/ or similar, because until you actually go external to your network, you cannot find your external IP. However, hardcoding such a URL is asking for eventual failure. You may wish to only perform this check if the current IP looks like an RFC1918 private address (192.168.x.x being the most familiar of these.
Failing that, you can implement your own, similar, service sitting external to the firewall, so you will at least know if it's broken.