TP-Link Router 'WAN IP: 0.0.0.0' DHCP Failure Fix

What it means

'WAN IP: 0.0.0.0' on a TP-Link router's status page means the router asked your modem (or ISP) for an IP address using DHCP and got nothing back — so the WAN address stays at the unassigned 0.0.0.0 placeholder.
The cable link is fine; the request is going unanswered.
The most common reasons are the modem being in router-mode itself (so it doesn't hand out an IP), the ISP locking the line to the previous router's MAC address, or the modem needing a power cycle to clear a stuck DHCP lease.

Affected Models

TP-Link Archer Wi-Fi 6 routers (AX10, AX23, AX55, AX73, AX1500, AX3000)
TP-Link Archer Wi-Fi 5 routers (C6, C7, C80, C1200)
Setups where the TP-Link router connects to a separate cable / fibre modem
Replacement-router scenarios after swapping the ISP's hardware
TP-Link routers set to Dynamic IP (DHCP) WAN connection type

Common Causes

Modem still has a stuck DHCP lease for the old router's MAC
ISP locks the line to a single MAC address (some cable ISPs)
Modem in router mode itself (it's not handing out a public IP)
WAN cable in the wrong port — yellow LAN instead of blue WAN
Connection Type set to Dynamic IP when ISP needs PPPoE
ISP service suspended or not yet activated
Modem firmware crashed and not responding to DHCP
Bad WAN cable that passes link but corrupts DHCP packets

How to Fix It

Power-cycle modem and router in order.

Unplug the modem from mains.
Unplug the router from mains.
Wait two full minutes — long enough for the modem's DHCP lease state to clear.
Plug the modem in first, wait until its lights settle (often 90–120 seconds).
Plug the router in.
This single sequence fixes the majority of 'WAN IP: 0.0.0.0' cases.
Check WAN connection type.

Network → Internet → Connection Type.
For most cable internet, this should be Dynamic IP.
For DSL or fibre with a PPPoE login, it should be PPPoE — Dynamic IP won't work and the WAN IP stays at 0.0.0.0.
Check your ISP's setup guide if you're not sure; getting Connection Type wrong is the silent cause of many WAN failures.
Confirm the cable is in the blue WAN port.

On the back of the TP-Link, the WAN port is the blue one (sometimes labelled 'Internet' or 'WAN').
Yellow ports are LAN.
If the cable from the modem is plugged into a yellow port, the router never gets a chance to ask for an IP.
Move the cable to the blue port, reboot, check WAN status.
Clone a known-good MAC address.

Some ISPs (especially older cable services like Virgin Media UK and some US cable providers) lock the connection to the MAC address of the first router they ever saw.
Network → Internet → Advanced → MAC Clone.
Set 'Use Current Computer's MAC' with a previously-working laptop connected, or manually enter the MAC of the previous router.
Save and reboot the modem and router.
Check the modem isn't in router mode.

If your ISP gave you an all-in-one modem-router and you're trying to put a TP-Link behind it, the ISP unit may be giving the TP-Link a private IP (192.168.x.x) instead of a public one — your TP-Link gets a 'real' IP from the ISP modem but it's a private/double-NAT one.
Either put the ISP unit into bridge mode (the modem-only setting), or live with double NAT (works for most things but breaks port forwards and some games).
Try a different Ethernet cable.

A cable that shows link but corrupts DHCP packets sounds rare but isn't.
Swap the WAN cable for a known-good Cat 5e or Cat 6 cable, ideally from a different roll.
If the WAN IP changes from 0.0.0.0 to a real address with the new cable, the original cable was bad even though it 'worked' (passed link).
Plug a laptop straight into the modem.

Unplug the WAN cable from the router and plug it into a laptop's Ethernet port.
Run ipconfig (Windows) or ifconfig (Mac) and see if the laptop gets a public IP.
If it does, the modem and ISP are fine — the router or its WAN settings are the issue.
If the laptop doesn't get a public IP either, the modem or the ISP line is the problem and you need to call the ISP.
Call your ISP to release the line.

If you've replaced an old router, the ISP's billing/provisioning system may still associate the line with the previous router's MAC.
Call the ISP, give them the new TP-Link's MAC (printed on the sticker on the bottom), and ask them to release the line and re-provision.
This is common with cable ISPs and sometimes fibre.

When to Call a Professional

WAN IP issues are owner-territory.
Call your ISP if a wired laptop plugged straight into the modem also fails to get a public IP — that's a line/account issue.
Call your ISP also if you've recently swapped routers and the line is locked to the previous router's MAC; many ISPs need to release the lock from their end before the new router can connect.

Frequently Asked Questions

Why does my TP-Link router show 'WAN IP: 0.0.0.0' when my old router worked fine?

Almost always because the modem or the ISP is still expecting the old router's MAC address.
When you replaced the router, the modem held onto the previous router's DHCP lease and won't hand out an IP to a new device until that lease expires (sometimes 24 hours) or the modem is power-cycled long enough for the lease to clear.
Some cable ISPs go further and lock the line to the first MAC they ever saw, which means even after a long power cycle the line refuses to talk to a different router.
The fix order: unplug the modem for two full minutes (clears most stuck leases); then if that doesn't work, MAC-clone the old router's address onto the new TP-Link (so the modem thinks it's the same device); then if that still fails, call the ISP and ask them to release the line lock and re-provision for the new MAC.
The router itself is innocent — it's just being denied service by the upstream side, which is why WAN IP stays stuck at 0.0.0.0.