FIELD DIAGNOSTIC — “HONEST LINK TEST

 

MARK’S FIELD DIAGNOSTIC — “HONEST LINK TEST”

Purpose:
Run three real-world tests that expose the true condition of a network link (jitter, loss, routing stability, sustained throughput).
Replaces Speedtest completely.

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COMMAND BLOCK (copy/paste and run as-is)

# 1. Stability & packet loss (50 probes to Cloudflare)
ping -c 50 1.1.1.1

# 2. Route quality (live traceroute + loss/jitter per hop)
mtr -rw 1.1.1.1

# 3. Sustained throughput test (TCP, real flow)
iperf3 -c iperf.scottlinux.com

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INTERPRETATION (brief)

1. ping

• 0% loss + tight latency → good link

• Loss > 1% → unstable

• Jitter swings > 30 ms → VPN, STT, games, Zoom all degrade

• “Destination Net Unreachable” → upstream routing failure (tower/backhaul dead)

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2. mtr

• Shows where packets die.

• Loss at hop 1 = tower or local NAT failure

• Loss at hop 2–3 = backhaul congestion/microwave link fault

• Loss only at far hops = upstream ISP issues

This is the “forensic” tool.

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3. iperf3

• Tests real, sustained throughput — no cheating, no smoothing.

• Smooth graph → link can carry load

• Bursts/stalls → congestion or jitter

• Disconnects → upstream failure

If iperf3 can’t connect at all → the link isn’t routing.

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CONCLUSION

This triple test reveals:

• jitter

• packet loss

• route instability

• tower congestion

• backhaul collapse

• VPN viability

• torrent viability

• STT reliability

• true usable bandwidth

Speedtest hides all of these.
This rig exposes them instantly.

 

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Righto — here’s your compact, portable field-diagnostic script.
Name it whatever you like; I’ll call it netcheck for simplicity.

This gives you:

• one command

• clean output

• no dependencies beyond mtr and iperf3 (install once)

• works anywhere

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1. The Script (netcheck)

Copy/paste this into a file:

#!/bin/bash

echo "===================================="
echo " Mark's Honest Link Test – netcheck "
echo "===================================="
echo

# ---- 1. PING TEST ----
echo "[1] PING: Stability + Loss"
echo "--------------------------"
ping -c 50 1.1.1.1
echo
echo

# ---- 2. MTR TEST ----
echo "[2] MTR: Route Quality (loss per hop)"
echo "--------------------------------------"
mtr -rw 1.1.1.1
echo
echo

# ---- 3. IPERF3 THROUGHPUT ----
echo "[3] IPERF3: Sustained Throughput Test"
echo "--------------------------------------"
iperf3 -c iperf.scottlinux.com
echo
echo "Done."

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2. How to install it

Save it somewhere sensible — I’d suggest:

~/bin/netcheck

Then make it executable:

chmod +x ~/bin/netcheck

If ~/bin isn’t already in your PATH, add it by editing ~/.bashrc:

echo 'export PATH="$HOME/bin:$PATH"' >> ~/.bashrc
source ~/.bashrc

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3. How to run it

Anytime, anywhere:

netcheck

That’s it.
No mucking around.
It runs the three honest tests in sequence:

• ping → stability

• mtr → route diagnosis

• iperf3 → sustained usable throughput

You get a complete truth readout of the link without touching Speedtest or any GUI.

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4. Notes

• If mtr or iperf3 aren’t installed, do this once:

sudo apt install mtr iperf3

• If iperf3’s test server is ever unreachable (rare), swap in Cloudflare’s:

iperf3 -c speedtest.wobcom.de

But the default one is rock solid.

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If you want a version that logs automatically to a timestamped file for later analysis, I can package that too.