Question

I’d like the user to be able to enter the MAC of a computer on the network. Once they’ve done that, it’ll add it to a list. The program will then ping all of those MACs on the list every time the class is called (I know this isn’t necessarily possible, but read on).

Normally I’d simply use IP addresses, but they aren’t static, and there are a -lot- of devices on the network that I don’t care about the connectivity of for this program. If they don’t respond, I’d like it to pop up a message box.

NOW, that being said, the only part I’m having trouble with is the actual part where I ping something. I know that an actual “ping” is not possible when it comes to MAC addresses, so how could I check for something like that? Alternatively, if it’s easier, I could also accept pinging something based on the computer name.

EDIT: I’d prefer not to have to use things like arp to find the IP addresses of the devices I want. Like I said though, I’m also interested in whether or not it’s possible to search for devices by name. Would that work?

Answer 1

If you have a properly administered environment, you should be using names. By properly administered environment, I’m primarily meaning having a DNS server on your local network.

I have something similar running that pings industrial ethernet devices. These are statically assigned addresses, so they don’t register themselves with DNS as a DHCP client would. I had our DNS administrator create records for them so I can just use their name. You’ll be better off in the long run as two years from now you’re going to have NO idea what that mac address in your list was referring to. When creating names, you can make them as descriptive as necessary.

EDIT: Here’s a function that takes a name as a string, looks up the associated IP from DNS, then pings. If DNS resolution fails or the ping doesn’t report success, the function returns false. It returns true otherwise. You should also log the exceptions for troubleshooting later, BTW.

public bool Check(string Name)
{
    //try dns resolution, if fails, quit reporting error
    IPAddress[] addresses = null;
    try
    {
        addresses = Dns.GetHostAddresses(Name);
    }
    catch (SocketException)
    {
        return false;
    }

    //ping remote address
    PingReply reply = ping.Send(addresses[0]);
    switch (reply.Status)
    {
        case IPStatus.Success:
            return true;
            break;
        default:
            return false;
            break;
    }
}

EDIT 2: Here are the namespaces I’m using in this project. Not sure what’s where exactly, but adding these three will get everything going.

using System.Net.NetworkInformation;
using System.Net;
using System.Net.Sockets;