Simple way to get MAC (Physical) address from inputted IP? - c#

Is there any command similar to this code to print out the MAC address or "hash code" of the IP stored in this variable? I have done some research and it looks like it can be a really complex to impossible task. But I think it is worth a shot to ask. (Edit: Any IP I search is an internal IP to my Network).
IPAddress addr = IPAddress.Parse(inputIP); //uses the input IP data into the addr variable to get host
IPHostEntry entry = Dns.GetHostEntry(addr); //Get hostname
Console.WriteLine("IP Address: " + addr);
Console.WriteLine("Host Name: " + entry.HostName); //output logic

You can't get the MAC address of an ip which is not on your local network (i.e. the internet). For local IP/MAC addresses you can do an arp lookup.
This SO Post explains the arp lookup.

Related

How to get all active IP address available on the network?

In this code find only system IP address and system name and I want to find all IP addresses and names available on network.
String StringHost;
StringHost = System.Net.Dns.GetHostName();
IPHostEntry ipEntry =System.Net.Dns.GetHostEntry(StringHost);
IPAddress[] address = ipEntry.AddressList;
for (int i = 1; i < address.Length; i++)
{
IP_Address_Datagridview.Rows.Add();
IP_Address_Datagridview.Rows[i].Cells[0].Value = StringHost;
IP_Address_Datagridview.Rows[i].Cells[1].Value = address[i].ToString();
}
The easiest way to see if a computer is on a local network is to use ICMP to 'ping' each address on your subnet. If the ICMP service is enabled on the IP address you are trying, (which is usually is on workstations, but not always on servers), then you will get a response.
Then you will want to take each valid IP address and do a reverse namespace lookup.

Constructing an IPAddress variable using Dns.GetHostEntry

My application is sending reports to another application (which maintains a database of reports) on the network with simple IPv4 addresses. I can construct a valid IPAddress in two ways:
string address = "200.1.2.41";
IPAddress ip1 = IPAddress.Parse(address);
IPAddress ip2 = (Dns.GetHostEntry(address)).AddressList[0];
If address represents an IP that is reachable, both methods are quick (though IPAddress.Parse is quickest). But if address is not reachable (eg. the server is off or the user has entered the wrong IP in Settings) then Parse is lightning quick...but Dns.GetHostEntry hangs for up to 9s.
I did a parameter-by-parameter check and the final variables ip1 and ip2 are identical. Given that Parse is always quick, and that I'm using standard four-octet IPv4 addresses only, is there any compelling reason to use the Dns.GetHostEntry method? Might I need Dns.GetHostEntry if I switch to IPv6 or named hosts like FOOD.HALL.01 in future?
If you just want get an instance of IPAddress for your IP address string representation, than yes, using the DNS for that purpose is absolute overkill.
All sorts of timeouts, latencies, etc. are absolute expected. At least compared to the purely local parsing and disecting of the string representation that happens in IPAddress.Parse(). What that does is, ask the DNS server to resolve the IP address string into a hostname "entry". From that you get the IP address back that you knew all along (albeit as string and not IPAddress).
Now, if you want to be able to "convert" host names into IP addresses in the future, then yes, you need to go via DNS.
But you could always do it in that manner (conceptually):
// First see if it is a valid IP address rep - fast.
IPAddress ip;
if (!IPAddress.TryParse(address, out ip))
{
// See if it is a hostname - slower.
ip = Dns.GetHostEntry(address).AddressList[0];
}
And yes, IPAddress.TryParse() (or Parse()) can handle IPv4 and IPv6 addresses.

how to get Network Compter Name and Netwok IP "Not internet IP" in Asp.Net

as i'm going to create Maintenance Request Page, so any employee can use this page from our local Network without internet, and i want to get the computer name and Ip for the one which made the request,
i search and read about this, but most if what i got it is: how to get the internet ip or host name and IP but my question is "how to get Network Compter Name and Netwok IP "Not internet IP" in Asp.Net"??
some of what i found it about Internet Ip and Host Info is:
using System.Net;
//Get the Host name:
string strHostName = string.Empty;
strHostName = Dns.GetHostName();
// Then using host name, get the IP address list..
IPHostEntry ipEntry = Dns.GetHostByName(strHostName);
//Get the IP address
IPAddress[] addr = ipEntry.AddressList;
for (int i = 0; i < addr.Length; i++)
{
Response.Write("IP Address {0}: {1} " + i + addr[i].ToString() + ", HostName: " + strHostName);
}
// end of host info.
and this way for internet info:
Response.Write("Your IP Address: " + Request.UserHostAddress + "<BR>");
Response.Write("Your Computer Name: " + System.Net.Dns.GetHostEntry(Request.UserHostAddress).HostName);
so is there any way to get the local Ip and Name of computer??
If you have DNS correctly configured to be updated with the names of computers as they connect and disconnect, then you can use reverse resolution to get from the client IP address back to the host name.
If your web site is inside the firewall, the connected user host address will be the internal address and can be resolved. If the site is hosted outside (or possibly in the DMZ) then you will not be able to get the name without requiring the user to provide it - or by running some trusted code on the client to access the local information.

Get All IP Addresses on Machine

How can I get all of the IP addresses attached to the machine that my application (C# NET Console app) is running on? I need to bind a WCF service to the primary IP address, and return a list of the full IP address list.
using System.Net;
string myHostName = Dns.GetHostName().ToString();
string ipAddress = Dns.Resolve(HostName).AddressList[0].ToString();
This is what I am using right now to get the Primary IP address, but I can't figure out how to get the rest to return them.
If I bind a WCF service to localhost:8000, will that expose it on the primary?
The DNS variants work across the network, but one DNS entry can have many IP addresses and one IP address can have many DNS entries.
More importantly, an address needn't be bound to a DNS entry at all.
For the local machine try this:
foreach (NetworkInterface netInterface in
NetworkInterface.GetAllNetworkInterfaces())
{
Console.WriteLine("Name: " + netInterface.Name);
Console.WriteLine("Description: " + netInterface.Description);
Console.WriteLine("Addresses: ");
IPInterfaceProperties ipProps = netInterface.GetIPProperties();
foreach (UnicastIPAddressInformation addr in ipProps.UnicastAddresses)
{
Console.WriteLine(" " + addr.Address.ToString());
}
Console.WriteLine("");
}
I think this example should help you.
// Get host name
String strHostName = Dns.GetHostName();
// Find host by name
IPHostEntry iphostentry = Dns.GetHostByName(strHostName);
// Enumerate IP addresses
foreach(IPAddress ipaddress in iphostentry.AddressList)
{
....
}
Edit:
"There's no such thing as a "primary" IP address.
The routing table determines which outward-facing IP address is used depending on the destination IP address (and by extension, the network interface, which itself can be virtual or physical)."
Why not just bind to 0.0.0.0 ?
That way you listen on all ips
You should probably bind to 0.0.0.0:8000, that will expose it on all available IP addresses and only bind to a particular IP address if the user/administrator demands so.
IPAddress[] localIPs = Dns.GetHostAddresses(Dns.GetHostName());
I think the OP is asking about how to get all addresses on a local NIC, not just those addresses known to DNS.
By primary he probably means the main address under "use the following IP address" in the adapter properties, and by "the rest" he probably means those listed in Advanced > (Additional) IP Addesses.
DNS will not necessarily know those.

Get host name from IP address

I have managed to get the connected clients IP with the code below but can't seem to get the hostname.
Globals.connectedIPAddress = "" + IPAddress.Parse(((
IPEndPoint)_client.Client.RemoteEndPoint).Address.ToString());
Well, not every IP address has a name. However, given the IPAddress you can use Dns.GetHostEntry to try to resolve it. Also note that if it's being a NAT router, you'll be getting the router's IP address rather than their actual machine.
And just to address the point in the comments, I agree that there's no point in ToString/Parse/ToString:
IPAddress address = ((IPEndPoint)_client.Client.RemoteEndPoint).Address;
Globals.connectedIPAddress = address.ToString();

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