--- title: "Quantum Fiber and CenturyLink modem login, restart, firmware and UPnP: a practical guide" url: "https://kilobat.app/routers/quantum-fiber" description: "Sign in to a Quantum Fiber or CenturyLink C4000 modem at 192.168.0.1: restart, update firmware, devices, UPnP, port forwarding, QoS, Wi-Fi channels and logs." --- Provider box · Quantum Fiber # Quantum Fiber and CenturyLink modem login, restart, firmware and UPnP Quantum Fiber and CenturyLink supply the same family of modem-routers, such as the C4000. You manage them in a browser at `192.168.0.1`, and restart them from the Quantum Fiber app. Quantum Fiber and CenturyLink modem Sign in `192.168.0.1` App Quantum Fiber app (iOS and Android) Password The Admin Username and Admin Password are printed on the sticker on the side, back or bottom of the modem. They differ from the Wi-Fi name and password on the same sticker. Models C4000XG, C4000, C3000, C2100, C844, C424, C3510, 360 WiFi pods **Checked 1 November 2026.** C4000, C3000, C2100, C844 and C424 modems (menus as of 2026); the C3510 menu differs slightly. Customers with a SmartNID and 360 WiFi pods manage Wi-Fi only in the Quantum Fiber app. ## Sign in to the Quantum Fiber and CenturyLink modem 1. Connect your Mac to the Quantum Fiber or CenturyLink network by Wi-Fi or cable. 2. Open `http://192.168.0.1` in a browser. If it warns that the site isn’t secure, continue. 3. Sign in with the Admin Username and Password from the modem sticker. 4. The menu shows **Modem Status**, **Quick Setup**, **Wireless Setup**, **Utilities** and **Advanced Setup**. Don’t remove the sticker: CenturyLink warns the default admin credentials can’t be retrieved if lost. You can change them under **Advanced Setup › Security › Administrator Password**. ## Restart it properly 1. Open the Quantum Fiber app and select **Network Information**. 2. Tap **Restart modem**, then **Restart** to confirm. 3. Wait up to 5 minutes for the success message, then tap **Close**. With a wall-mounted SmartNID, never unplug the green fibre wires underneath it, and contact support before any reset. A factory reset (**Utilities › Restore Defaults**) erases your Wi-Fi name and password. ### Restart by hand 1. Unplug the power cord from the back of the modem. 2. Plug it back in and wait 2 to 3 minutes. 3. On a C4000, the light ring turns green when it is connected. ### In the modem settings 1. Sign in at `192.168.0.1` and select **Utilities**. 2. Select **Reboot**. ### Schedule a restart Neither Quantum Fiber nor CenturyLink documents a scheduled restart. **Kilobat can help.** Kilobat Pro’s [router check-up](https://kilobat.app/docs/home-network#router-checkup) learns how fast this router usually answers, says when a restart is due, and checks the next day whether it helped. ## Update the firmware Firmware updates arrive automatically over the network, and they don’t reset your settings. You can check by hand. 1. Sign in and select **Utilities › Upgrade Firmware**. 2. If **Upgrade Status** says **Firmware is up to date** or **N/A**, you’re done. 3. Otherwise select **Download** and save the file to your Mac. 4. Select **Browse**, pick the file, then select **Upgrade Firmware**. 5. Wait about 5 minutes while it installs and the modem restarts. A C4000 light ring blinking amber-green or amber-white means a firmware update is running. Don’t unplug it then. ## See connected devices 1. Sign in and select **Modem Status**. 2. Open the **Device Table** to see every device on your network. 3. For Wi-Fi details, select **Utilities › Wireless Diagnostics** and choose **Client Table** or **Client Diagnostics**. Wireless diagnostics isn’t on every model. With 360 WiFi, the Quantum Fiber app can set device schedules that pause, block or allow access. **Kilobat can help.** Kilobat’s [new-device alerts](https://kilobat.app/docs/home-network#new-devices) tell you when a device you haven’t seen joins your home Wi-Fi. **Tools › Devices** lists what answers on the network, and you can name each one. ## UPnP and port forwarding The modems support UPnP. CenturyLink documents a UPnP switch and a separate **UPnP NAT-T** state, with a list of current mappings. 1. Sign in and select **Advanced Setup**. 2. Under **Security**, select **UPnP** in the left sidebar. 3. Enable UPnP, and set the UPnP NAT-T state. 4. Click **Apply**. With UPnP on, any device on your network, including malware, can open ports through the modem. Keep NAT enabled: CenturyLink warns that turning it off opens the modem to intrusion. ### Port forwarding 1. Select **Advanced Setup › Security › Port Forwarding**. 2. Choose the device from the list or enter its IP address. 3. Enter the start and end ports and select the protocol. 4. Choose **All IP Addresses** or a specific remote address, then click **Apply**. **Application Forwarding** on the same menu forwards ports by application name instead. ### NAT-PMP Neither Quantum Fiber nor CenturyLink mentions NAT-PMP. **Kilobat can help.** On supported routers, Kilobat’s [call reports](https://kilobat.app/video-calls) can read available traffic counters, read-only, to identify another device that was busy when a call froze. Correlation does not prove the cause. Kilobat never opens ports. ## Prioritise calls and gaming On a C4000, QoS switches on automatically when you add a priority rule. 1. Sign in and select **Advanced Setup › QoS**. 2. Choose the device from the list or enter its IP address. 3. Select the traffic direction to control: upstream, downstream or both. 4. Select high, medium or low priority, then click **Apply**. On older models, tick **Enable QoS** first and pick a QoS type or a custom rule. The C4000XG also has Dynamic QoS for smoother streaming. **Kilobat can help.** Run Kilobat’s [stutter test](https://kilobat.app/guides/recipes/test-call-stutter) before and after you change priorities, to see whether calls really got smoother. ## 2.4 and 5 GHz, and the channel The C4000XG uses Smart Connect: one Wi-Fi name, with the modem choosing the faster band for each device. Other models let you set 2.4 and 5 GHz separately. 1. Sign in and select **Wireless Setup**. 2. If offered, pick **2.4 GHz** or **5 GHz** in the left sidebar. 3. Select **SSID Setup** to name each band’s network. 4. Click **Apply**. ### Change the channel 1. Under **Wireless Setup**, pick the band, then **Radio Setup**. 2. Select a channel, the channel width and the power level. 3. Click **Apply**. The modem picks the channel automatically, and CenturyLink advises changing it only when your provider tells you to. **Utilities › Wireless Diagnostics › Channel Analysis** ranks channels by noise. **Kilobat can help.** Kilobat shows which band and channel your Mac is on, and `kilobat channels` suggests the least crowded channel. More in [crowded Wi-Fi channels](https://kilobat.app/guides/wifi-channel-congestion) and [Wi-Fi on a Mac](https://kilobat.app/wifi-analyzer-mac). ## Mesh: which node a device uses Quantum Fiber 360 WiFi uses pods managed in the Quantum Fiber app. 1. Open the Quantum Fiber app and tap **360 WiFi Pods**. 2. Tap **Add Wireless Pod**, then **Ready to scan QR Code**. 3. Scan the QR code on the back of the pod, or type its serial number in capitals. 4. Wait for the success screen showing your network and all pods. To move a pod, unplug it, move it and plug it back in; it reconnects on its own. Restarting the SmartNID restarts the pods too. **Kilobat can help.** When your Mac moves to another node or band, Kilobat’s Health says so, so a weaker node isn’t taken for a router problem. See [find a better Wi-Fi spot](https://kilobat.app/guides/recipes/find-better-wifi-spot). ## Guest network There is no labelled guest network in the modem settings. CenturyLink documents up to four Wi-Fi networks under **SSID Setup**, which you can use for guests. 1. Sign in and select **Wireless Setup › SSID Setup**. 2. Pick an unused network from the drop-down list. 3. Select **Enable SSID** and give it a name. 4. Set its password under **Wireless Security** and click **Apply**. CenturyLink doesn’t say whether extra networks are kept apart from your main one. With 360 WiFi, guests can join by scanning the QR code in the Quantum Fiber app. **Kilobat can help.** Kilobat can show a network as a QR code, so guests join with their phone’s camera: [share Wi-Fi with a QR code](https://kilobat.app/guides/recipes/share-wifi-qr-code). ## DNS settings CenturyLink documents entering your own primary and secondary DNS only for static IP setups, under **Advanced Setup › WAN Settings**. On a normal dynamic connection, set DNS on the Mac instead. **Kilobat can help.** Before you change DNS, [compare resolvers with Kilobat](https://kilobat.app/guides/recipes/pick-faster-dns) to see which answers fastest from your home. ## Connection status and logs 1. Sign in and select **Modem Status › Connection Status** for the firmware, connection and IPv4 address. 2. Check **Internet Status** for authentication failures and session time. 3. Select **Utilities › System Log** for a timed list of system actions, or **Firewall Log** where offered. 4. Run **Utilities › Diagnostic Test** to check the WAN, PPP and DNS. On a C4000, solid green means connected, solid red a network failure. Quantum Fiber also has an outage checker at `quantumfiber.com/outagetool`. **Kilobat can help.** When the line keeps dropping, Kilobat’s [provider report](https://kilobat.app/docs/health#report) lists outages, latency and speed tests against your plan, ready to send to your provider. ## Manuals and downloads - [Quantum Fiber: C4000XG modem user guide](https://www.quantumfiber.com/support/equipment/user-guides/c4000xg-modem.html) - [Quantum Fiber: Modem GUI settings guide](https://www.quantumfiber.com/support/equipment/user-guides/gui-settings.html) - [Quantum Fiber: C4000 data sheet (PDF)](https://www.quantumfiber.com/content/dam/quantumfiber/equipment/downloads/C4000_Datasheet_updated_120921.pdf) Links go to the maker’s own pages. ## Questions **What is the admin password for 192.168.0.1?** It is on the sticker on the side, back or bottom of the modem, next to the Admin Username. It isn’t your Wi-Fi password. **Do I need to update the firmware myself?** Usually not. Updates are installed automatically through the network, but you can check under **Utilities › Upgrade Firmware**. **Can I reset a SmartNID?** Quantum Fiber says not to; contact its support first. Reset only modem-router gateways such as the C4000. ## Sources - [Quantum Fiber Support: Modem settings in the GUI](https://www.quantumfiber.com/support/equipment/user-guides/gui-settings.html) - [Quantum Fiber Support: C4000XG modem user guide](https://www.quantumfiber.com/support/equipment/user-guides/c4000xg-modem.html) - [Quantum Fiber Support: How to restart your SmartNID or modem](https://www.quantumfiber.com/support/equipment/troubleshooting/restart-your-modem.html) - [Quantum Fiber Support: How (and when) to reset your modem](https://www.quantumfiber.com/support/equipment/troubleshooting/modem-reset.html) - [Quantum Fiber Support: How to install a 360 WiFi pod](https://www.quantumfiber.com/support/services/360-wifi/add-wifi-pod.html) - [Quantum Fiber Support: 360 WiFi FAQs](https://www.quantumfiber.com/support/services/360-wifi/faqs.html) - [CenturyLink Help: Security settings (port forwarding, UPnP, NAT)](https://www.centurylink.com/home/help/internet/modems-and-routers/advanced-setup/security-settings.html) - [CenturyLink Help: Configure QoS on your modem](https://www.centurylink.com/home/help/internet/modems-and-routers/advanced-setup/qos.html) - [CenturyLink Help: Wireless setup](https://www.centurylink.com/home/help/internet/modems-and-routers/wireless-setup.html) - [CenturyLink Help: Utilities menu](https://www.centurylink.com/home/help/internet/modems-and-routers/utilities.html) - [CenturyLink Help: How to check your modem firmware version](https://www.centurylink.com/home/help/internet/modems-and-routers/utilities/update-modem-firmware.html) - [CenturyLink Help: Modem status menu](https://www.centurylink.com/home/help/internet/modems-and-routers/modem-status.html) - [CenturyLink Help: WAN settings](https://www.centurylink.com/home/help/internet/modems-and-routers/advanced-setup/wan-settings.html) - [CenturyLink Help: Advanced setup in the modem settings](https://www.centurylink.com/home/help/internet/modems-and-routers/advanced-setup.html) Checked on 1 November 2026. ## See what your router can’t tell you Kilobat is a Mac menu-bar app that watches the network from your side: which app is using it, whether the Wi-Fi, the router or the provider is slow, and why a call froze. [Download for Mac ↓](https://kilobat.app/downloads/Kilobat-1.31.1.dmg?via=site) ``` brew install seifip/kilobat/kilobat ``` ## More router guides - [ARRIS SURFboard Wi-Fi cable modem](https://kilobat.app/routers/arris-surfboard): SURFboard Wi-Fi cable modems combine a DOCSIS cable modem and a Wi-Fi router in one tower, and you buy them yourself to use with cable internet services such as Xfinity. - [AT&T Fiber Gateway](https://kilobat.app/routers/att-gateway): The BGW320 (now called an All-Fi Hub) and the older BGW210 are the gateways AT&T supplies for AT&T Fiber and AT&T Internet. - [Calix GigaSpire](https://kilobat.app/routers/calix-gigaspire): The Calix GigaSpire is the Wi-Fi router that many fibre and local internet providers hand out. - [Cox Panoramic Wifi Gateway](https://kilobat.app/routers/cox-panoramic-wifi): The Panoramic Wifi Gateway is the combined cable modem and Wi-Fi router that Cox rents out.