When your network is acting up — no internet despite Wi-Fi being connected, weird IP conflicts, stuck on an old subnet — releasing and renewing your IP forces your computer to start fresh. It's the second-most-useful network troubleshooting trick after "reboot the router."

Windows

Open Command Prompt (search → cmd), then run:

ipconfig /release
ipconfig /renew

The first command tells your DHCP client to give the current IP back to the router. The second requests a new one. Run both — separate steps.

For more aggressive cleanup, also run ipconfig /flushdns to clear cached DNS lookups.

Mac

Apple menu → System Settings → Wi-Fi → Details… → TCP/IP tab → click Renew DHCP Lease.

From Terminal: sudo ipconfig set en0 BOOTP && sudo ipconfig set en0 DHCP (en0 = Wi-Fi; use en1 for Ethernet on most Macs).

Linux

For systemd-based distros (most modern Linux):

sudo dhclient -r && sudo dhclient

Or restart the network service: sudo systemctl restart NetworkManager (most desktops) or sudo systemctl restart systemd-networkd (servers).

When this fixes things

• You see a 169.254.x.x APIPA address
• Wi-Fi shows connected but no internet
• Two devices ended up with the same IP (IP conflict)
• You changed routers or moved networks and the old config stuck

When it doesn't fix things

If renew also fails or you keep getting the same broken IP, the issue is upstream: router, modem, or ISP. Power-cycle them in order: modem → router → device. Wait 60 seconds between each. More on the Mac "self-assigned" failure mode.

Try it now

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