How To Add A Second Internet Line To Your Home Office For Backup Connectivity

Adding two lines can bolster your continuity

Daniel Rosehill
3 min readMay 6, 2021

If you’re looking to make your home working environment more robust, then one of the most useful steps you can take is establishing backup communication supplies.

During the last few months, my main internet service provider (ISP) here in Israel has been doing a pretty lousy job at getting me connectivity. My internet tends to go down for hours at a time. Sometimes the intermittent outages can do on for days.

In Israel, we have a somewhat strange means of delivering interest to consumers.

Consumers need to pick both a sapak (ISP) and tashtit (infrastructure provider) when purchasing residential internet. Various ISPs support different infrastructures but are responsible for basic customer support.

And while ultra fast fiber optic is being deployed throughout the country, there are plenty of areas — including where I live, in fairly central Jerusalem — that simply don’t have it available yet.

Last week, one of the outages struck just when I was about to dial in as a guest for a podcast. I decided that that was the last straw and that it would indeed be worth paying double for a second internet line.

We now have subscriptions to both the two types of tashtit available in our area — specifically Hot and Bezeq. The first line is fast (at least on the download, the upload is atrocious). But it’s unreliable. The second line is slow but reliable. While neither is an idea solution, by combining the two we can cover all bases.

Besides signing up for a separate line, all you need to make this work for your desktop is a $3 piece of plastic.

How To Set Up Dual Ethernet Internet

If you’re using WiFi to connect to the internet, then you don’t need to take extra steps. Just connect to whatever network offers the best performance. And if one goes down, use the other.

With desktop (I’m a desktop and ethernet user) you won’t want to be shuffling around ethernet cabling every time you want to shift connections. Thankfully all you need is a $3 piece of plastic.

It took me a little while to find the component I was looking for because I would instinctively call it an ethernet KVM. An ethernet switch is clearly something else entirely. The preferred terminology for a device to manually switch between two ethernet networks appears to be an RJ45 network switcher.

Here’s an example of what you’re looking for:

Then all you have to do is run ethernet from both routers to the switch and then run another line from the output to the computer. If your main ethernet connections goes down, just press a button to switch to the backup line.

(There are more technically elaborate ways to handle this kind of setup on a software level, but I reckon the simple piece of plastic push trick will be good enough for most home internet users).

Take Your Redundancy Even Further By Adding A Cellular Line

If you want to take things even further you could supply to two ISPs as I have done (your main and fallback connection) and also provision a 4G/LTE (or 5G) router running off a data SIM card.

This would provide you with even more redundancy. Even if both wired networks went down, you could switch over to cellular for uninterrupted connectivity.

What you’ll need for this:

  • A cellular router
  • A data SIM card subscription

How It Looks Setup

Here’s how my switch looks connected. A and B, on the left, are the two ethernet inputs from the routers. The button toggle is on the top of the switch. And the output end runs into the ethernet port on my desktop.

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Daniel Rosehill

Daytime: writing for other people. Nighttime: writing for me. Or the other way round. Enjoys: Linux, tech, beer, random things. https://www.danielrosehill.com