How to Fix WiFi Not Working After Getting New ISP Equipment: Modem, Router, and Configuration Guide
Just had new ISP equipment installed and WiFi still isn’t working? From modem provisioning to PPPoE credentials and MAC cloning, here’s exactly how to diagnose and fix the most common setup problems.
Your ISP just swapped out old equipment—or you bought your own modem and router to replace the rental—and now WiFi isn’t working. Before you call your ISP’s support line and wait on hold, work through this guide. The vast majority of post-install problems have straightforward fixes you can handle in under 15 minutes.
Step 1: Power-Cycle in the Right Order
This single step fixes more problems than anything else. Power-cycling out of sequence is a surprisingly common cause of a failed setup. Follow this sequence exactly:
- Unplug both your modem and router from power.
- Wait 30 seconds.
- Plug in the modem first. Wait 60–90 seconds until its indicator lights stabilize (typically a solid “Online” or “Internet” LED).
- Plug in the router. Wait another 60 seconds for it to fully boot.
- Try connecting a device.
Why order matters: your router needs to receive a DHCP lease from the modem before it can obtain an external IP address. If the router powers on before the modem is ready, it gets no WAN address and your entire network stalls.
Step 2: Check If the Modem Is Provisioned
If you brought your own cable modem (or received a new one from your ISP), it must be provisioned on your ISP’s network. This is especially critical for cable internet (Xfinity, Spectrum, Cox, Optimum). An unprovisioned modem will receive no internet signal even if all the indicator lights look normal.
How to Check
Connect a laptop directly to the modem via Ethernet—bypass the router entirely. Open a browser. If you see a modem activation page served by your ISP, follow those steps. If no page loads at all, call your ISP and provide the modem’s MAC address and serial number (printed on the device label). They can add it to their provisioning system in minutes.
Fiber customers (AT&T, Verizon Fios, Google Fiber): the ONT (optical network terminal) installed by the technician typically doesn’t need this step, but your ISP may need to register the router’s WAN MAC address before granting internet access. Ask when you call.
Step 3: Set the Correct WAN Connection Type
Your router needs to know how your ISP assigns an IP address to its WAN port. The three common types are:
- Dynamic IP (DHCP): Used by most cable and fiber providers. The router gets an IP address automatically.
- PPPoE: Common with DSL (AT&T, CenturyLink/Lumen) and some fiber ISPs. Requires a username and password provided by your ISP.
- Static IP: Primarily business accounts. You manually configure a fixed IP address, subnet mask, and gateway.
Log into your router’s admin panel (typically 192.168.1.1 or 192.168.0.1). Find the WAN or Internet settings and confirm the connection type matches your ISP. If you’re on PPPoE but the router is configured for DHCP, the WAN IP field will show 0.0.0.0 and nothing will work. Your ISP’s welcome letter, account portal, or support line can confirm your connection type and PPPoE credentials.
Step 4: Clone Your MAC Address
Some ISPs—particularly older cable providers—bind internet access to the MAC address of the last device they provisioned on your line. If you replaced an ISP-provided gateway with your own equipment, their system may still expect the old hardware’s MAC address and refuse to assign an IP to the new device.
How to Clone
In your router’s admin panel, look for a “MAC Clone” or “MAC Spoofing” option under WAN settings. Enter the MAC address from your old router or gateway (found on its label or in your ISP’s customer portal). Alternatively, power-cycling the modem for five or more minutes often clears the ISP’s cached MAC lease and allows the new hardware in automatically—no cloning needed.
Step 5: Reconnect Devices to the New WiFi Network
New ISP equipment—especially an ISP-provided gateway—ships with a default WiFi name (SSID) and password printed on the device label. Your existing devices won’t automatically reconnect because the SSID or password has changed.
- Reconnect each device manually using the new SSID and password, or
- Log into the router and change the SSID and password to exactly match your old network. Devices will reconnect without reconfiguration on their end.
Also review the security protocol. Modern routers default to WPA3 or a WPA2/WPA3 mixed mode. Older smart home devices (Amazon Echo, Ring cameras, older Nest thermostats) can silently fail to connect to WPA3-only networks. If those devices won’t join, temporarily set the 2.4 GHz band to WPA2-only as a test. See our guide on WPA3 transition mode issues for a full walkthrough.
Step 6: Fix DNS If Websites Won’t Load
If you can reach IP addresses (pinging 8.8.8.8 succeeds) but websites won’t load by domain name, DNS is the culprit. This happens after ISP equipment changes when the router inherits a stale or incorrect DNS server address from the modem.
In your router’s DNS settings, manually enter a reliable public DNS server:
- Google DNS: 8.8.8.8 and 8.8.4.4
- Cloudflare DNS: 1.1.1.1 and 1.0.0.1
Save and reconnect your devices. This resolves most “connected but no internet” situations not caused by a WAN IP problem.
Step 7: Update Router Firmware
New routers occasionally ship with firmware containing known bugs or ISP compatibility issues. Log into the admin panel immediately after setup and check for firmware updates. Most modern routers from ASUS, TP-Link, Netgear, and Eero include a one-click firmware update in the admin UI or their companion app. A firmware update sometimes resolves WAN detection issues that no amount of reconfiguration will fix on its own.
When to Call Your ISP
If the modem shows no upstream signal lights, or you’ve worked through every step above and still can’t get a WAN IP, the problem is likely on the ISP’s side. Issues they need to address:
- Line signal problems: On cable, downstream power outside −7 to +7 dBmV or SNR below 30 dB indicates a degraded line.
- Provisioning failures: Their back-end system didn’t correctly activate your modem.
- Account issues: Inactive service, billing hold, or a technical block on the account.
Before calling, run a speed test with your laptop connected directly to the modem via Ethernet. A zero result or total failure is concrete evidence the problem is upstream of your router—share that with support to speed up diagnosis. For general slow-speed troubleshooting after your setup is stable, see our guide on why WiFi gets slow.
Quick Fix Checklist
- Power-cycle modem first, then router—wait 60–90 seconds at each step
- Test with a laptop connected directly to the modem via Ethernet to isolate the issue
- Confirm modem provisioning with your ISP (cable customers especially)
- Set the correct WAN type: DHCP, PPPoE (with credentials), or Static IP
- Clone the old MAC address if your ISP was locked to previous hardware
- Reconnect devices to the new SSID, or set your old network name and password on the new router
- Switch 2.4 GHz to WPA2-only if older smart home devices won’t connect
- Set Google (8.8.8.8) or Cloudflare (1.1.1.1) DNS if sites won’t load
- Update router firmware immediately after setup
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