No Internet After Router Reboot

Step 1: Verify local IP assignment

Check that your device has a valid local IP (not 169.254.x.x, which indicates APIPA/DHCP failure):

# Linux / macOS
ip addr show
# or
ifconfig

# Windows (Command Prompt)
ipconfig /all

A healthy result shows an IP in ranges like 192.168.x.x, 10.x.x.x, or 172.16-31.x.x with a valid gateway.

Step 2: Ping your default gateway

# Linux / macOS
ping -c 4 $(ip route | grep default | awk '{print $3}')

# Windows
ipconfig | findstr "Default Gateway"
ping 192.168.1.1

If the gateway responds, your LAN is healthy. If it doesn't respond, the router itself may not have finished booting.

Step 3: Check the router WAN status

Log in to your router admin panel (commonly http://192.168.1.1 or http://192.168.0.1) and inspect the WAN/Internet status page. Look for:

• WAN IP Address (should be a public or ISP-assigned IP, not 0.0.0.0)
• Connection type (DHCP, PPPoE, Static)
• Connection status (Connected / Disconnected)

Step 4: Test DNS resolution separately

# Linux / macOS — try resolving using a public DNS server directly
nslookup google.com 8.8.8.8
dig @1.1.1.1 google.com

# Windows
nslookup google.com 8.8.8.8

Step 5: Check ISP DHCP lease timing

If the router uses DHCP to obtain its WAN IP, the ISP's DHCP server may not have renewed the lease yet. Wait 60-90 seconds after the router fully boots, then recheck. Some ISPs have lease times of 24 hours and may briefly deny a renewal if the MAC address appears new.

Step 6: Force a WAN DHCP renewal from the router

# On a Linux-based router or via SSH to the router
# Release current lease
dhclient -r eth0   # replace eth0 with WAN interface name

# Request a new lease
dhclient eth0

Most consumer routers expose a "Release/Renew" button in the WAN settings page.

Option A: Wait and retry (most common fix)

Most ISPs renew DHCP leases automatically within 60-120 seconds of the router coming back online. Simply wait 2 minutes and try again.

Option B: Release and renew WAN IP from router admin panel

1. Log in to http://192.168.1.1 (or your router's admin IP)
2. Navigate to WAN or Internet settings
3. Click Release IP, wait 10 seconds, then click Renew IP
4. The router should obtain a new public IP from the ISP within 30 seconds

Option C: Power-cycle the modem separately

If you have a separate modem (ISP-provided device before your router):

1. Power off both the modem and router
2. Wait 30 seconds
3. Power on the modem first — wait until all status lights are stable (1-2 minutes)
4. Power on the router
5. Wait another 60 seconds for DHCP negotiation

Option D: For PPPoE connections (fiber/DSL)

# Verify PPPoE credentials are still saved in router config
# In router admin: WAN > Connection Type > PPPoE
# Re-enter username and password provided by ISP
# Click Save and then Connect

Option E: Flush client-side DNS cache

After router recovers, flush the DNS cache on affected devices:

# macOS
sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

# Linux (systemd-resolved)
sudo systemd-resolve --flush-caches

# Windows
ipconfig /flushdns

• Configure your router to use a DHCP lease time of at least 24 hours to reduce re-negotiation friction after reboots
• For PPPoE connections, enable "auto-reconnect" in the router's WAN settings so credentials are retried automatically
• Set up a secondary DNS server (e.g., 1.1.1.1 as backup to 8.8.8.8) to avoid single-point DNS failures
• Use a UPS (uninterruptible power supply) for the modem and router to avoid unnecessary reboots during brief power fluctuations
• Document your ISP connection type (DHCP/PPPoE/Static) and credentials in a secure location so troubleshooting is faster