Get All IP Addresses on Machine

Question

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?

What's a "Primary IP" address? Aren't all IP addresses born equal? — Cosmin Prund, Mar 11 '11 at 10:33
The AddressList is a collection and you're only using the 1st element. Does that collection always produce as single element for you? — Maciek, Mar 11 '11 at 10:33

score 66 · Answer 1 · edited Feb 22 '23 at 06:24

66

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("");
}

edited Feb 22 '23 at 06:24

Uwe Keim

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answered Mar 11 '11 at 11:04

This is a valuable answer. – IneedHelp Nov 29 '20 at 22:03
Identify IPv4 addresses using: addr.Address.AddressFamily == AddressFamily.InterNetwork – oferei Feb 22 '22 at 11:18
The accepted answer gives me 127.0.0.1 and its IPv6 counterpart. This answer gives everything. If it matters, I'm on Windows 11 (with latest updates at the time of writing) – nurchi Aug 19 '22 at 17:20

Alex Hope O'Connor · Accepted Answer · 2015-07-14T04:35:11.707

10

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)."

edited Jul 14 '15 at 04:35

answered Mar 11 '11 at 10:34

Alex Hope O'Connor

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This will typically return what you want but on occasion if there is a misconfiguration in DNS on the system you can have some issues with Dns.GetHostByName. – kthompson Jul 10 '15 at 16:03
This answer actually does not work in my machine. It only returns 127.0.0.1, even though I have an active Wifi connection with a real ip-address. – avl_sweden Sep 18 '15 at 14:24
This answer has a bug, it does not return all the local machine IP addresses because an IP address don't need to be bound to a DNS host. Using NetworkInterface.GetAllNetworkInterfaces like in the answer below should be the accepted answer. Don't use this code! – Darxis Apr 14 '21 at 23:00

score 6 · Answer 3 · answered Mar 11 '11 at 10:36

6

Why not just bind to 0.0.0.0 ?
That way you listen on all ips

answered Mar 11 '11 at 10:36

Fredrik Leijon

2,792
18
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1

I was looking for this to bind my WCF service to all IPs. Thanks! – Fadi Chamieh Oct 08 '14 at 11:05

score 1 · Answer 4 · answered Mar 11 '11 at 10:36

1

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.

answered Mar 11 '11 at 10:36

Cosmin Prund

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score 0 · Answer 5 · answered Mar 11 '11 at 10:32

0

IPAddress[] localIPs = Dns.GetHostAddresses(Dns.GetHostName());

answered Mar 11 '11 at 10:32

StefanE

7,578
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4

Please explain why this code would help the OP solve their problem. – Sumner Evans May 08 '15 at 04:04
Thank you!! That's add all the ip to a list of string – Yanga Jul 04 '17 at 14:59

score -2 · Answer 6 · answered Apr 21 '16 at 08:33

-2

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.

answered Apr 21 '16 at 08:33

Daniel Clarke

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2

It is better suited as a comment, I presume. But I didn't downvote. – Zimano Apr 30 '18 at 10:30

Get All IP Addresses on Machine

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