Does anyone know if an hardware ethernet on/off switch exists to buy? Or if it would be possible to build one?

I currently have an issue in my software development environment that can only be resolved by pulling the ethernet cable out of my my machine. I know it does not make much sense, but it is the fastest solution I have to solving this issue (see my open question on StackOverflow)


What I am looking for is some type of dongle that would sit between my ethernet cable and my machine. I envision a simple on/off switch on it. Does this exist? If not, would I be able to build one? Is there some physical limitation to doing this?

I am really looking for a hardware solution here. As far as a software solution is concerned, I have exhausted most of the possibilities (firewalls, turning off network connection, etc) and most have either not worked or caused some other issues.


I took the advice of @tom-wijsman and implemented a software solution. I created a small C# application that adds and deletes an entry in the HOSTS file. This entry will point our database server to a nonexistent IP address. Its kind of a hack, but it solves our problem.

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  • I've never heard of one, but theoretically, it would just require that the switch remove the connection to the copper conductors in the RJ 45 plug. I don't know how easy that would be to build, but it is certainly plausible. – MaQleod Aug 31 '11 at 15:17
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    Why not just disable the adapter in the OS instead of pulling the plug? – Ƭᴇcʜιᴇ007 Aug 31 '11 at 17:05
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    @Jon: If it's trying to contact a database, can't you add the IP/Server the database is on to the hosts files with the IP Kind of a nasty workaround, but you wouldn't have to plug the cable every time. It might also be interesting to see what Wireshark has to say... – Tamara Wijsman Aug 31 '11 at 17:52
  • @techie007: Unfortunately, disabling the adapter via the OS does not solve my problem. I have tried that many times. When I do that, the software I am running knows that I do not have a network connection and will not let me continue. When I pull the plug, the software does not know the connection is gone. – Jon Sep 6 '11 at 14:42
  • @tom-wijsman: I could possibly do that... But I would probably have to do it once and then reverse it every time this issue came up. I was looking for a much quicker solution. Its possible that I could script the addition/deletion of the entry in the hosts file. I will look into this further. Either way... I was looking for a hardware solution here. – Jon Sep 6 '11 at 14:45

You could try something like this. While not an on/off switch it would do the same thing:

enter image description here

I imagine what you could do, is place the cat-5 into the switch and then switch to the other port when you need to turn it off.

Note: while this looks like a RJ-11 it says it's a RJ-45 (Cat-5) switch. I would triple check to make sure.

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    Wow, I remember having one of those back in the day! I always wondered if they really needed all that volume, or if the box contained mostly air. – Pops Sep 2 '11 at 19:11
  • I've popped open one of those... was a KVM with a big switch like that. The switch itself extended almost to the back of the case, and the rest was wires and air. Lots of free space in there. – Ryan Gooler Sep 2 '11 at 19:46
  • you could just take it apart and mount the necessary parts to something smaller. But seems like a lot of trouble for a quick fix. – James Mertz Sep 2 '11 at 22:19

I have never heard or seen of such a device. in lieu of a better answer:

Depending on your operating system, it may be easiest to write a small script to enable/disable the port.

If however you want hardware, All I can recommend is you use a 1-2 meter ethernet cable from your computer to your desk (or wherever convenient), and plug it in to a ethernet coupler.

enter image description here

(Non cross over, but, in most cases it won't make a difference)

Then plug the cable that was in your machine in to this.

This should make it a lot easier than what you are currently doing (unless you are using a laptop!)


Low tech solution: Use a small extra network switch and just pull the plug or use a switched socket-outlet for its wall-wart.


Or you can simply build a "lag switch".
Like this.
Just use a switch which can hold all the cables. There you go.

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    So that's how all those teenage gamers get behind me randomly. I don't think you need to get a switch that would handle all wired. The orange effectively does the same thing that the OP wants. – James Mertz Sep 3 '11 at 17:37
  • @KronoS: Uhm. If you use a lag switch you would continue your momentum till a point you are standing still, you continue to move from where you stood still. It does not give you any advantage over other players. People that get behind you is more likely for another reason, starting to listen to footsteps in your headset is a good start to catch those that want to sneak by or leave their camping spot... – Tamara Wijsman Sep 6 '11 at 19:34

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