ISP connectivity loss: quick fix for sudden drops

I know that feeling when your internet cuts out and you're halfway through something important. It's annoying. Let's fix it.

The fix that works 8 out of 10 times

Most ISP connectivity loss isn't a real outage. It's your router or modem holding onto a bad IP lease from your ISP. The real fix? Force a new DHCP lease. Here's how:

1. Open Command Prompt as admin. Hit Windows Key, type cmd, right-click Command Prompt, pick Run as administrator.
2. Type these commands one at a time, hit Enter after each:

ipconfig /release
ipconfig /renew
ipconfig /flushdns

Wait 30 seconds between each command. The /release drops your current IP. /renew asks your router for a fresh one. /flushdns clears old DNS cache that can cause weird routing issues.

If you're on Wi-Fi and /renew hangs, plug in an Ethernet cable for a minute. That forces the adapter to grab a new lease faster.

Why this works

Your ISP gives your modem a temporary IP address called a DHCP lease. It expires after a set time — usually 24 hours to 7 days. When it expires, your router should get a new one automatically. But routers are dumb. They sometimes hold onto the old lease and keep asking for it. The ISP's server says "that IP is gone" and sends nothing back. You get a connection timeout.

By manually releasing and renewing, you force your modem to ask for a completely fresh IP. It's like waking your router up and saying "start over." Almost always fixes it.

Less common variations of the same issue

Sometimes the above doesn't cut it. Here are three other scenarios that look like ISP connectivity loss:

1. Modem cache overload

Your modem stores routing tables and DHCP info. After a power flicker or long uptime (over 30 days), that cache gets corrupted. Fix: unplug the modem AND router from power for a full 60 seconds. Not 10 seconds. 60. Plug modem back in first, wait for all lights to stabilize (usually 2 minutes), then plug in router.

2. IP conflict on your local network

If two devices on your home network try to use the same local IP, your router gets confused. You'll see internet dropping only on some devices. On Windows 11 or 10, run ipconfig /all and check if your IP is within the router's DHCP range (usually 192.168.1.2 to 192.168.1.254). If it's outside that range, you have a static IP conflict. Set your adapter back to automatic.

3. ISP-side packet loss that mimics drops

Your connection stays up, but web pages hang. This is often ISP throttling or a bad node. Open Command Prompt and ping 8.8.8.8 -t for 30 seconds. If you see "Request timed out" more than 5% of the time, call your ISP. They have a bad line. This command runs until you hit Ctrl+C.

Prevention tips to avoid future drops

I've been running help desks for years, and these three things stop 90% of repeat ISP connectivity loss:

• Reboot your modem and router once a month. Set a calendar reminder. Clears the cache before it gets bad.
• Keep your router firmware updated. Most people never check. Log into your router (usually 192.168.1.1), look for "Firmware Update" or "Check for Updates." Do it every 3 months.
• If you use Wi-Fi, switch to 5 GHz if possible. 2.4 GHz is crowded — neighbors, microwaves, baby monitors all fight for the same airwaves. 5 GHz gives you less interference and fewer "drops" that feel like ISP problems but are really local radio mess.

One last thing: if the issue happens every day at the same time (like 6 PM), that's congestion. Your ISP oversells bandwidth in your neighborhood. The fix there is either upgrading your plan or switching to a provider with fiber. Nothing else helps.

Try the lease release first. I'd bet that fixes it. If not, try the 60-second power cycle. If still no luck, you might have a hardware issue — check if your modem's "Online" light blinks red when the drop happens. That's a dead giveaway your ISP's line is bad.