> ## Documentation Index > Fetch the complete documentation index at: https://docs.derekdinh.com/llms.txt > Use this file to discover all available pages before exploring further. # Troubleshooting No Internet Connection on Windows and Mac > Follow these step-by-step instructions to diagnose and resolve a complete loss of internet connectivity on Windows and macOS systems. Loss of internet connectivity can stem from a wide range of causes — a loose cable, a frozen router, a corrupted network adapter, or a misconfigured IP address. Before escalating to IT support, work through the steps below in order, as each one rules out a common root cause and builds on the last. Start with the simplest possible cause: a cable that has come loose or an indicator light that has changed state. * Verify that the **Ethernet cable** (if applicable) is firmly seated in both your computer's network port and the router or wall jack. Listen for the audible click of the connector locking in place. * Check the **lights on your router and modem**. A healthy setup typically shows a solid or slowly blinking WAN/Internet light. A red or absent light on the WAN port indicates a signal problem between your modem and the ISP. * If you are on Wi-Fi, confirm that **Wi-Fi is enabled** on your device and that you are associated with the correct network (not a neighbor's network or a stale profile). * Try connecting a **second device** to the same network. If that device also has no internet, the problem is almost certainly with the router, modem, or ISP — not your computer. If every device on the network has lost internet but the router itself appears healthy, call your ISP directly before proceeding further. They can confirm whether there is a line outage in your area. A full power cycle clears the router's memory, refreshes its external IP lease, and re-establishes the handshake with your ISP. 1. **Unplug the modem** from its power source. 2. **Unplug the router** from its power source (if it is a separate device from the modem). 3. Wait a full **60 seconds**. This allows capacitors to discharge and the ISP's equipment to register that your modem has gone offline. 4. Plug the **modem** back in first and wait until its status lights stabilize (usually 30–60 seconds). 5. Plug the **router** back in and wait for it to complete its boot sequence (another 30–60 seconds). 6. Attempt to load a website. If you have a combined modem/router unit, a single 60-second power cycle is sufficient. Avoid using the router's reset pinhole button — that performs a factory reset and erases your Wi-Fi credentials and custom settings. If your device has not received a valid IP address from the router, it cannot route traffic to the internet. An address beginning with `169.254.x.x` indicates a failed DHCP lease. **Windows (PowerShell or Command Prompt):** ```powershell theme={null} ipconfig /all ``` Look for the **IPv4 Address** field under your active adapter. A valid private address will start with `10.`, `172.16.`–`172.31.`, or `192.168.`. If you see `169.254.x.x`, your device could not reach the DHCP server. **macOS / Linux (Terminal):** ```bash theme={null} ifconfig # or on modern Linux distributions: ip addr show ``` Look for the `inet` line on your active interface (`en0` on macOS, `eth0` or `enp3s0` on Linux). A `169.254.x.x` address here also signals a DHCP failure. **To request a fresh IP lease on Windows:** ```powershell theme={null} ipconfig /release ipconfig /renew ``` **On macOS**, go to **System Settings → Network → \[Your Interface] → Details → TCP/IP** and click **Renew DHCP Lease**. Running `ipconfig /release` immediately drops your network connection. Make sure you do not need active network access (e.g., a remote session) before running it. Stale or corrupted DNS cache entries can prevent domain names from resolving, which looks identical to having no internet even when the underlying connection is healthy. **Windows:** ```powershell theme={null} ipconfig /flushdns ``` Expected output: `Successfully flushed the DNS Resolver Cache.` **macOS (Ventura / Sonoma):** ```bash theme={null} sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder ``` **Linux (systemd):** ```bash theme={null} sudo systemd-resolve --flush-caches sudo systemd-resolve --statistics # confirm CacheSize dropped to 0 ``` After flushing, try loading a website again. If pages load successfully, the issue was a stale DNS cache. DNS flushing is safe to run at any time and does not affect stored passwords, cookies, or browsing history. Your browser may prompt you to re-enter credentials on a few sites, which is normal. A disabled or error-state adapter will silently prevent all connectivity. **Windows:** 1. Press **Win + R**, type `ncpa.cpl`, and press **Enter** to open Network Connections. 2. Find your active adapter (e.g., **Ethernet** or **Wi-Fi**). 3. If it shows a red X or the word **Disabled**, right-click it and choose **Enable**. 4. If it shows a yellow warning triangle, right-click → **Diagnose** to run the Windows Network Diagnostics wizard. You can also check adapter status and reset it via PowerShell: ```powershell theme={null} # List all adapters and their status Get-NetAdapter # Disable and re-enable a specific adapter (replace 'Ethernet' with your adapter name) Disable-NetAdapter -Name "Ethernet" -Confirm:$false Enable-NetAdapter -Name "Ethernet" -Confirm:$false ``` **macOS:** 1. Open **System Settings → Network**. 2. Confirm your active interface shows a **green dot** next to it. 3. If it is orange or red, toggle it off and back on using the gear icon, or click **Make Service Inactive / Make Service Active**. Outdated or corrupted network adapter drivers are a common cause of persistent adapter errors on Windows. Open **Device Manager** (search from the Start menu), expand **Network Adapters**, right-click your adapter, and choose **Update driver**. Ping allows you to isolate exactly where the connection is failing — your local gateway, your ISP's infrastructure, or a remote server. ```powershell theme={null} # 1. Ping your local default gateway (replace with your actual gateway IP) ping 192.168.1.1 # 2. Ping a known public IP address (Google's DNS server) ping 8.8.8.8 # 3. Ping a hostname to test DNS resolution ping google.com ``` **Interpreting results:** | Test | Result | Meaning | | --------------------------------------- | ------------------- | ----------------------------------------------------------------- | | Gateway ping fails | Request timed out | Router unreachable — check physical connections or restart router | | Public IP ping succeeds, hostname fails | DNS failure | Follow the DNS flush steps above or change your DNS server | | Public IP ping fails | ISP or WAN issue | Contact your ISP | | All pings succeed but browser fails | Browser/proxy issue | Reset browser settings or check proxy configuration | Some servers and routers block ICMP (ping) by default. A failed ping to `8.8.8.8` does not always mean connectivity is lost — also try `tracert 8.8.8.8` (Windows) or `traceroute 8.8.8.8` (macOS/Linux) for a more detailed path analysis. If none of the above steps restore connectivity, gather the following information before contacting IT support or your ISP — it will significantly speed up the diagnosis. * **Full output of `ipconfig /all`** (Windows) or `ifconfig` / `ip addr show` (macOS/Linux) * **Results of your ping tests** to the gateway, `8.8.8.8`, and `google.com` * **Router/modem model number** and current firmware version (found in the router's admin page) * **When the problem started** and whether any changes were made beforehand (OS update, new software, moved office) * **Number of devices affected** — just yours, or the whole network? * **Event Viewer logs** on Windows: open Event Viewer → **Windows Logs → System** and filter for errors around the time connectivity was lost Do not attempt to modify router firmware, reset network hardware to factory defaults, or change ISP-provisioned settings without explicit authorization from IT. These actions can cause broader outages affecting other users.