I want to get the IP of my PC (the local IP taken from the router).
I could get the IP but with other IPs on the network. Is there a method to extract only the needed IP without getting all the IPs in an array and then choosing from them the needed one?
Code tried:
string strHostName = string.Empty;
strHostName = Dns.GetHostName();
IPHostEntry ipHostEntry = Dns.GetHostEntry(strHostName);
IPAddress[] address = ipHostEntry.AddressList;
foreach (var item in address)
{
Console.WriteLine(item.ToString());
}
The result of this code is a bunch of IPs found on the network including my IP (broadcast domain, IPv6 and similar stuff but not other devices' IPs). I want to get only my actual IP without getting all as the code will be published on a machine which I cannot monitor the IP all the time.
You are missing to filter the IP by type (v4). Anyway you can have multiple IP v4 addresses on your PC (for example you can have 2 interfaces, LAN and Wi-Fi).
The following code gets the list of available IP v4.
List<string> ips = new List<string>();
System.Net.IPHostEntry entry = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName());
foreach (System.Net.IPAddress ip in entry.AddressList)
if (ip.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
ips.Add(ip.ToString());
Related
I am using following code to connect to remote host:
IPHostEntry hostname = Dns.GetHostEntry("172.29.65.33");
IPAddress address = hostname.AddressList[0]; // IndexOutOfRangeException
...
My question is why AddressList is empty? Host is there, no SocketException is thrown...
Some details: customer has upgraded Windows XP to 8.1 and then all troubles begun.
I've read this and this topic, but unfortunately they are not useful to fix an issue, therefore asking it again.
Instead of resolving addresses via Dns
IPHostEntry hostname = Dns.GetHostEntry("172.29.65.33");
IPAddress address = hostname.AddressList[0];
...
IPEndPoint end = new IPEndPoint(address, port);
it can be simply parsed
IPEndPoint end = new IPEndPoint(IPAddress.Parse("172.29.65.33"), port);
This will eliminate all problems (socket exception, empty address list, etc.) related to using Dns.
Right now i have the requirement to find some PC's Hostname by his IP Address and i solved this problem with this function:
/// <summary>
/// Returns the DNS Name of IP Address without the Domain.
/// </summary>
public string GetDNSNameFromReverseLookUp(string ip)
{
IPAddress hostIPAddress = IPAddress.Parse(ip);
IPHostEntry hostInfo = Dns.GetHostEntry(hostIPAddress);
return hostInfo.HostName.Substring(0, hostInfo.HostName.IndexOf('.'));
}
But i'm not happy with this substring() solution of the problem.
Is it allowed to use this function this way? Or do i have to fear some network issues in the future? Are there better (more secure) ways to get to the hostname without domain?
I'm looking for an more network secure solution, not another way to handle strings. As mentioned in the comments I fear a little bit, that not every OS returns the Hostname in the format:[Hostname].[Domainname].
You will get an error if pc are not joined to a domain. Since the (dot) is not found, and so the use of split function is the most reasonable. I've already checked.
Try this
public string GetDNSNameFromReverseLookUp(string ip)
{
IPAddress hostIPAddress = IPAddress.Parse(ip);
IPHostEntry hostInfo = Dns.GetHostEntry(hostIPAddress);
return hostInfo.HostName.Split('.')[0];
}
We're trying to obtain all ip addresses and hostnames of machines on local network, we have a display box(BrightSign box) which is connected to local network and we want to have all information about that box. We can find ip address of it, but cannot get host name. So we can't determine which ip adresses is assigned to that box. (We can learn the ip address of the box by using its own program; but we want to detect automatically)
here the code we use in c#
`
public void scan(string subnet)
{
Ping myping;
PingReply reply;
IPAddress addr;
IPHostEntry host;
for (int i = 1; i < 255; i++)
{
string subnetn = "." + i.ToString();
myping = new Ping();
//string data = "aa";
//byte[] buffer = Encoding.ASCII.GetBytes(data);
//PingOptions optionss = new PingOptions(64, true);
int timeout = 1000;
reply = myping.Send(subnet + subnetn);
if (reply.Status == IPStatus.Success)
{
try {
addr = IPAddress.Parse(subnet+subnetn);
host = Dns.GetHostEntry(addr);
txtHosts.AppendText(subnet + subnetn + host.HostName.ToString()+"\n");
}
catch {
}
}
}
}`
if we use this code, system can detect all ip but not host names belongs to telephone and the box i mentioned.
Briefly, we need to have all machine name and ip addresses on local network.
So, do you guys have any idea what's the problem and what can we do to solve this issue. We made some research and tried some ways. We tried to send ping the ip address which we cannot take the hostname and we realized that if ttl of machine is set to 64, we cannot take the hostname, but if its ttl is 128, we can manage to learn the hostname, i also adjusted ping settings to test this challenge, but i still have problem.
I am looking forward to hearing your response.
Thank you all.
Machine name could be DNS or NETBIOS or something else. I recommend you check out NMAP and see what it can do. If you want to emulate that, you can ask about a specific requirement. For example, getting a DNS name means querying the DNS server, a computer wont reply with a name just from an ICMP ping. If the computer security settings allow it, you can do a netbios query, or use WMI, or if you are in a domain, query the domain server.
I don't know what brightsign is, but there is no law that says a device must have a DNS name, some appliances just use IP address and thats it. Also there's no law that says a device must respond to ping or any other protocol.
Assume there are two systems; System1 and System2.
System1 - Windows XP
System2 - Linux.
I have installed a WPF application on System1. A user on System2 connects to System1 via a Remote Desktop Connection and launches the WPF application.
In the WPF application, I can get the local IP address and Windows Login Name for System1 using the following code.
private String GetIP()
{
string strHostName = "";
strHostName = System.Net.Dns.GetHostName();
IPHostEntry ipEntry = System.Net.Dns.GetHostEntry(strHostName);
IPAddress[] addr = ipEntry.AddressList;
return addr[0].ToString();
}
String WinUserName_withNetwork = System.Security.Principal.WindowsIdentity.GetCurrent().Name;
String WinUserNameOnly = System.Environment.UserName;
My problem is I want the IP address and user name of the user logging in from System2.
What do I need to do in order to get that IP address and user name?
As far as I understand the question you want to know the IP address of the System2 from the System1 computer and the name of the user logged thru the remote connection. Am I right?
Assuming that you can use environment variables to gather this information:
CLIENTNAME: contains the name of the computer connected thru remote desktop.
USERNAME: contains the name of the user logged in.
Hope this helps.
Refer following Code:
IPHostEntry iPAddress = DNS.GetHostByName (HostName);
IPAddress [] IPAdd = iPAddress.AddressList;
for (int j = 0; j < IPAdd.Length; j++)
{
Console.WriteLine ("IP Address {0}: {1} ", j, IPAdd[j].ToString ());
}
Can also refer THIS doccument.
Simply open a command prompt / shell and type IPCONFIG
Look for an IP4 address. Quite often you'll see it's "127.0.0.1". Type NSLOOKUP to get the name of the computer.
Hope this helps
Using C# Winforms I am trying to automatically detect the local machines IP address through which it can connect to a particular remote DNS/IP address.
One senario is running over a VPN, with the remote address being 10.8.0.1 and local address being 10.8.0.6, netmask of 255.255.255.252
Iterating through the local addresses and checking if the remote and local are on the same subnet obviously fails and I am unsure of how else to do this.
Here is some sample code that should get you the information you're looking for. It creates a UDP socket and calls Connect() on it (effectively a NOOP), and then checks the local address.
static EndPoint GetLocalEndPointFor(IPAddress remote)
{
using (Socket s = new Socket(remote.AddressFamily,
SocketType.Dgram,
ProtocolType.IP))
{
// Just picked a random port, you could make this application
// specific if you want, but I don't think it really matters
s.Connect(new IPEndPoint(remote, 35353));
return s.LocalEndPoint;
}
}
static void Main(string[] args)
{
IPAddress remoteAddress = IPAddress.Parse("10.8.0.1");
IPEndPoint localEndPoint = GetLocalEndPointFor(remoteAddress) as IPEndPoint;
if (localEndPoint == null)
Console.WriteLine("Couldn't find local address");
else
Console.WriteLine(localEndPoint.Address);
Console.ReadKey();
}
Note that this is effectively an implementation of this answer, but in C#.
The routing table determines which local port to use. I don't know of a way from C# to get it other than to run the route print CLI command. If there is a network match it uses that port, otherwise it uses the default route.
http://www.csharp-examples.net/local-ip/
Give that a shot.