Quick Network Diagnostic Checklist

It's Monday morning. The network is slow. Three employees have complained. Someone already called your IT guy.

Before you spend $150/hour on a support call, work through this checklist. You might solve it in 10 minutes.

The quick wins (do these first)

1. Restart the affected devices Computers, phones, tablets—restart them. You'd be surprised how many problems disappear after a reboot.

2. Restart the router and modem Unplug both. Wait 30 seconds. Plug the modem back first, wait for it to fully boot, then plug in the router.

3. Check if it's just one device or everyone

• If one device has problems, the issue is that device.
• If all devices have problems, the issue is the network or internet.
• If some devices have problems, those devices share something (same switch, same WiFi network, same access point).

4. Try a different connection If on WiFi, try an ethernet cable. If on ethernet, try WiFi. This isolates whether the problem is the connection type or something else.

Internet connectivity checks

Can you reach anything?

Open Command Prompt (Windows) or Terminal (Mac). Type:

ping 8.8.8.8

• If this works: Your internet connection is fine. Problem is DNS or the specific application.
• If this fails: Your internet connection is down. Check your provider.

Is DNS working?

Try accessing a site by IP address:

ping 142.250.80.46

(This is Google's IP)

• If you can ping the IP but not google.com: DNS is broken.
• Fix: Flush your DNS cache or change DNS servers to 8.8.8.8 / 8.8.4.4

What's your actual speed?

Go to speedtest.net and run a test. Compare to your expected speeds.

• If speeds are much slower than expected: Possible congestion, throttle, or equipment issue.
• If speeds are zero: Connection is down.

WiFi-specific checks

How many bars do you have? One or two bars means weak signal. Move closer to the access point.

Are you on 2.4GHz or 5GHz? 2.4GHz has better range but is more congested. 5GHz is faster but doesn't penetrate walls as well.

• If on 2.4GHz and slow, try switching to 5GHz.
• If on 5GHz and range is poor, 2.4GHz might work better.

How many WiFi networks are visible? Too many overlapping networks cause interference.

• On Windows: Click the WiFi icon, see how many networks appear.
• On Mac: Hold Option while clicking the WiFi icon for channel information.

Are you connected to the right network? Verify you're on YOUR network, not a neighbor's or a guest network.

Wired network checks

Check the cable Look at the ethernet cable:

• Is it plugged in all the way?
• Is the connector damaged?
• Try a different cable if you have one.

Check the port The wall jack or switch port might be dead:

• Try a different port on the switch.
• Try a different wall jack if available.

Check the lights Most network equipment has status lights:

• Link light: Should be on when cable is connected.
• Activity light: Should blink during traffic.
• No lights: Cable issue, port issue, or equipment issue.

Application-specific checks

Is it one app or multiple apps?

• One app: Problem is that app or its servers.
• Multiple apps from the same vendor: Vendor issue.
• Multiple unrelated apps: Network issue.

Can you access the app's status page? Search for "[app name] status page" or check downdetector.com.

When did the problem start?

• Right after a reboot or update? Roll back or troubleshoot the change.
• After new software installed? Uninstall and test.
• End of month? Could be data cap issues.
• Same time every day? Could be scheduled backups or updates.

Speed and performance issues

Check for bandwidth hogs Log into your router and look at connected devices. Any unknown devices? Any devices using a lot of bandwidth?

Check for interference

• Microwave running? Degrades WiFi significantly.
• Cordless phones on 2.4GHz? Interference source.
• Dense walls or metal structures? Signal degradation.

Check your data cap Some business internet plans have monthly data caps. Exceeding them can result in throttling.

Document what you find

Before you call for help, document:

• What devices are affected
• When the problem started
• What you've already tried
• What error messages appear
• Whether the problem is consistent or intermittent

This information helps your IT person solve the problem faster, which saves you money.

The nuclear option: Factory reset

If you've tried everything and nothing works, a factory reset of your router or access point might help—but only do this if:

• You've backed up the configuration
• You know how to reconfigure it
• You're prepared to set up all your network settings from scratch

Factory reset is rarely the right answer for complex problems. It creates more work than it saves.

When to call for help

Call immediately if:

• You suspect a security breach or ransomware
• Multiple devices are behaving strangely (possible malware)
• You've lost access to administrative accounts
• The problem involves compliance-relevant systems

Call after you've worked through the checklist if:

• The problem persists after basic troubleshooting
• You don't know what the error messages mean
• You need equipment replaced
• The problem is recurring and you want a permanent fix

Call your ISP first if:

• You have no internet connectivity at all
• You've power-cycled everything and still have no connection
• You hear clicking or see blinking lights on the modem

What it costs

| Scenario | Your Time | Professional Cost | |----------|-----------|-------------------| | Restart fixed it | 5 minutes | $0 | | DNS change fixed it | 10 minutes | $0 | | Router replacement | 1-2 hours | $150-$500 for parts, $100-$300 labor | | ISP issue | 30 minutes on phone | $0 (usually) | | Complex network problem | 2-4 hours | $300-$800 |

Working through this checklist first saves you money. It also helps you communicate the problem more clearly when you do need professional help.