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How to check if ethernet is connected?

Started by Anshul, Feb 19 2012 08:44 PM

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10 replies to this topic

#1 Anshul

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Posted 19 February 2012 - 08:44 PM

What's the proper method to check if the ethernet cable is connected, or if the Netduino+ has an IP Address, or both? Thanks

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#2 Nathan Baker

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Posted 23 February 2012 - 02:54 AM

Hrm, this is a good question. I have to do this at some point to make my client more stable, just been lazy.

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#3 Chris Walker

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Posted 23 February 2012 - 03:33 AM

Hi Anshul, If you're using DHCP, you can check your current IPAddress through the NetworkInterface object (in Microsoft.SPOT.Net). Chris

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#4 clem0338

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Posted 29 October 2012 - 02:00 PM

Hi, I know that i'm digging an old thread but I have the similar question and I must manually set the IP address (so no DHCP). Is there any way to do it ? Thanks. Cédric

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#5 Nicky

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Posted 29 October 2012 - 03:16 PM

Except from NetworkAvailbilityChanged event, which cannot be used to detect the initial state, I suggest making somekind of request, wrapped in a try-catch ... if it fails, no network.

ntools
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Netduino Plus Go Module · Xml Parser
http://ntools.codeplex.com/

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#6 clem0338

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Posted 29 October 2012 - 05:10 PM

Except from NetworkAvailbilityChanged event, which cannot be used to detect the initial state, I suggest making somekind of request, wrapped in a try-catch ... if it fails, no network.

Thanks,

but it is exactly what i don't want. Let's explain myself:
The network can be down or unplugged.
When I'm trying to do the Socket.Connect, my ND+ is totally stuck (and all my threads

...)
It seem's to be a well known bug (corrected in MF 4.3 beta)
http://netmf.codeple...m/workitem/1396 for more info

So, i'm looking for a way to "check" the network before Socket.Connect even after boot up ...

Thanks anyway, regards

Cédric

Edit:
More info
http://netmf.codeple...m/workitem/1181
http://www.dotnetsol...word-of-warning

Didn't work with 4.1 neither 4.2 (Flashed for this bug)

I still have an IP address in memory even unplugged (DHCP trick)

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#7 andybareweb

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Posted 29 October 2012 - 05:14 PM

Hi,

I know that i'm digging an old thread but I have the similar question and I must manually set the IP address (so no DHCP).

Is there any way to do it ?

Thanks.

Cédric

Hi Cédric:

var interfaces = Microsoft.SPOT.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces();
                foreach (var networkInterface in interfaces)
                {
                    Debug.Print(networkInterface.IsDhcpEnabled ? "Dhcp Enabled" : "Static Ip");
                    Debug.Print(networkInterface.IPAddress);
                    if (networkInterface.IsDhcpEnabled)
                    {
                        networkInterface.EnableStaticIP("192.168.0.9", "255.255.255.0", "192.168.0.1");
                    }
                }

This prints out whether you're already Dhcp Enabled or Static, and if Dhcp it sets to static.

You'd probably want to be a little cleverer around releasing leases if you want to be friendly to your dhcp server, but otherwise the above works.

Regards
Andy

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#8 caEstrada

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Posted 29 October 2012 - 05:59 PM

Use any network operation inside a {Try/Catch} and then, check the Exception Value and Message, works perfect.

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#9 Nobby

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Posted 30 October 2012 - 12:45 AM

One method I use is to create a socket which is a listener using IPAddress.Any for the binding. The listener will be created if the network is up or down but you can call Socket.Poll(). It will throw a SocketException if the network is down with an error code 10050. The only time this approach fails is if you power the ND+ up and it initially isn't connected to the switch/router. There's some bug which is apparently being fixed in 4.3 where network connectivity to the ND+ is impossible under this start-up condition but the ND+ internally believes connectivity is fine after you plug the network cable in.

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#10 clem0338

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Posted 08 November 2012 - 10:10 AM

Many thanks for your answers and please, excuse me for the while I took. To andybarweb: I may be static IP or DHCP (from configuration file on SD). I don't want to force a static IP To caEstrada: Already in a try/catch. The problem is Socket.Connect never returns even with an exception To Nobby: This can be an half way solution. This will be OK for the ethernet activity test but, if my server is down, the problem's remains. Thanks to all. Cédric