How can I test if my data cabling, punch-downs & jacks are 100%?

Notice: Page may contain affiliate links for which we may earn a small commission through services like Amazon Affiliates or Skimlinks.


If it does not exist ? I am probably building it.
Feb 3, 2018
New Jersey, USA
I know when I run a cable, punch it down, crimp, and plug the two ends into this LED tester, the lights indicate that I have a good connection on each pair. Then, I plug into my switch & server / computer - and the link goes up 1gb, connect all good.

Is it all good at that point ? I do not know. What happens if someone shuffles a cabinet around, shakes a cable somewhere, bumps up against the a cable in patch panel, or there was some microscopic corrosion on any of the terminal connects? I am skeptical.

Is there a log in Linux (outside of the standard syslog) I can check to see about any errors in my packets, or anything that would suggest I have line noise or a not-so-good connection? Am I just being overly cautious and paranoid?


Well-Known Member
Nov 10, 2015
If doing this at home, a quick check with a cheapie cable tester is about as far as you need go. After that, it either works or it doesn't. If on the other hand you are doing this as a professional installer, then you'll need a good meter that you can use to verify the wire/ cable run with. A good meter will run a battery of tests, everything from checking for split pairs to TDR to measure discontinuities and length to checking for near and far end crosstalk and etc. Patch cables at the panels can also be checked, both in and out of circuit.

As for what happens when you bump up against terminations, like most things in life, there is a multitude of possibilities. If it fails either now or later, it will be pretty obvious to the end user. It may even be that the user ran over their patch cable with their chair for a week beforehand, without even thinking about the outcome of doing so. Environment also plays a part here, anywhere that moisture levels are high needs due consideration. Sometimes you'll get a poor connection at a panel developing due to dust, moisture and oxidation occurring on the terminals. A quick pull and re-insertion of the jack is normally all that's needed to clear such things, at least until it happens again :)

If you are concerned about errors, you could use a packet sniffer like wireshark on a mirrored port at the switch to log specific traffic for later inspection, or the switch itself may even be capable of logging such events. Generally though, fixed horizontal and vertical wiring when properly specified and installed is rarely an issue later, without some unforeseen event occurring like rodent damage or a misinformed contractor cutting through something. Patch cables on the other hand, move the responsibility of proper care into the hands of end users. Most of the time I see infrastructure issues it's either bad patch leads or chatty NIC's (Flapping).

All that said, life happens, nothing is forever, faults occur, you just have to troubleshoot and deal with them as and when :)


If it does not exist ? I am probably building it.
Feb 3, 2018
New Jersey, USA
Ok I think I got it. I have a LED cable tester which shows the basic connection of all the pairs have continuity. I have experience punching these down, its not my first time. I just wanted to expand my knowledge of other tools I was not using that could give me some more information.

After that, it either works or it doesn't.
Ok, well that will wrap this question up. I got your advice, so if it works for 15 minutes - it will probably work forever.

As far as the wire-shark goes, I have been there. That is a waterfall of information that is so overwhelming. I find myself reading the all the messages all night and forgetting to go to sleep, like when DEFRAG was first invented and I watched the entire animation from end-to-end on a whole 20mb hard drive.

Mostly what I have learned was when I had friends and co-workers around with me to share their knowledge. I use wire-shark when I'm debugging my UTP/TCP code to trace messages.


Oct 7, 2019
Pittsburgh, PA
Unless you need your cables 'certified' to spec with a fancy scanner to pass some auditing requirement you've already done enough due diligence. I work for a medium size company with a large (probably 1/2 a mile spread) campus, and around 40 worldwide locations. We don't test a single cable or care so long as it works as expected.

If you use a basic tester to make sure the little lights light up that's pretty decent. If you have a nicer tester then that gives you a nice warm fuzzy feeling. If the link goes up and data flows you've done 95% of it really.

Here's what I do for home stuff. (I'd do the same at work, but we have a 3rd party wire monkey vendor so I don't have to)

-Make my connections
-Test cabling with a Klein Scout Pro 2 LT (~$200) and remotes, this tests for physical issues, crossed wires, gives cable length, etc. At home I document the data in a spreadsheet just because.
-Test my laptop on the line. Sometimes I'll do a speed test, sometimes just basic pings or ping floods. So long as I get reasonable speed and no dropped packets or high latency I'm happy as can be.

That's it! If it works it works 99% of the time. If it breaks you fix it later, you can't plan or avoid that now. Like mentioned above there are too many outside factors to consider.

If you want a nicer test, do look into those Klein testers, but I'd suggest the higher end ones with the length tester and the numbered remotes for wire identification.

Good luck!


Post Liker and Deal Hunter Extraordinaire!
Jul 21, 2017
So my parents house was wired in the mid-1990s when no one was doing this in houses. We used 400Mhz rated wire that was super expensive at the time. It worked great for 100Mbps.

Then gigabit arrived and after getting a gigabit switch, it was obvious some ports just were not working at speed. The simple test I used was just 2 laptops and iperf, one at the switch and one at the port. If I got near gigabit speeds, it was gigabit, if I didn't, it was still running at 100Mbs. And it was obvious why some were at 100Mbps and I've got a lot of ports to re-terminate someday...

This was a pretty quick and dirty test that stress tested each line pretty well. Hope this helps!