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Using your C4000 modem

Learn about using your C4000 series modem/router, including features and speed specifications, popular modem settings, and troubleshooting. You can also watch a video about controling WiFi on your C4000.

Recommended CenturyLink modem

C4000 modem front and back
C4000 modem setup instructions

C4000 features

  • Secure WiFi compatible (with leased modem)
  • WiFi 6 technology with dual-band 2.4 GHz and 5 GHz 802.11ax
  • Smart Connect single wireless network (SSID): Auto-selects the fastest band for each device
  • Single LED status light 
  • Dynamic QoS: Prioritizes data through the router for smoother streaming
  • Standards-based WiFi WPA3 security

Speed specifications

This router comes in multiple versions with different specifications. The one you have depends on your internet connection type. Click to open the specific models below for speeds and downloadable info sheets.

The C4000BG and C4000BZ are tested and certified to run at these speeds* on the CenturyLink® High-Speed Internet network:

ADSL2 connection - up to 40 Mbps with pair-bonding
VDSL connection - up to 140 Mbps with pair-bonding

Axon C4000BG info sheet (PDF)

Zyxel C4000BZ info sheet (PDF)

*Customer speed experiences will vary, particularly when accessing the internet wirelessly from different devices. Maximum download/upload speeds given are via a wired connection. Internet speeds are not guaranteed due to conditions outside of network control, including customer location, devices, equipment, and access over a wired or wireless connection; see centurylink.com/internetpolicy for more information.

The C4000LG and C4000LZ are tested and certified to run at these speeds* on the CenturyLink® High-Speed Internet network:

ADSL connection - up to 7 Mbps
ADSL2 connection - up to 20 Mbps
VDSL connection - up to 100 Mbps

Axon C4000LG info sheet (PDF)

Zyxel C4000LZ info sheet (PDF)

*Customer speed experiences will vary, particularly when accessing the internet wirelessly from different devices. Maximum download/upload speeds given are via a wired connection. Internet speeds are not guaranteed due to conditions outside of network control, including customer location, devices, equipment, and access over a wired or wireless connection; see centurylink.com/internetpolicy for more information.

The C4000XG is tested and certified to run at speeds up to 940 Mbps* on the CenturyLink® Fiber Internet network.

Axon C4000XG info sheet (PDF)

*Customer speed experiences will vary, particularly when accessing the internet wirelessly from different devices. Maximum download/upload speeds given are via a wired connection. Internet speeds are not guaranteed due to conditions outside of network control, including customer location, devices, equipment, and access over a wired or wireless connection; see centurylink.com/internetpolicy for more information.

Diagram of the C4000XG modem

Diagram of the C4000XG modem

Top modem settings and tasks

Learn how to manage your internet and WiFi network using your modem. Below are some of our most popular topics. You can also visit the modem settings guide for a complete overview of settings and options.

Guide to the C4000 status light
Manage your devices with Secure WiFi
2.4 vs. 5 GHz wireless frequencies
Connect devices to your WiFi network
Connect using WPS
WAN setup (advanced)

Learn how to access your modem settings and how you can use them to manage your network.

Modem Settings Guide

This modem comes with Secure WiFi

When leased, our newer modems like this one come with Secure WiFi, which lets you control some advanced features through the CenturyLink app. Note that these in-app features WILL NOT BE AVAILABLE in the modem settings GUI:

  • Access scheduler
  • Service blocking
  • Website blocking

Modem troubleshooting tips

  • Did you know?  If your internet connection is spotty or slow, the best place to start is to reboot your modem.

  • Still not running right? Check to see if your modem firmware is up to date.

Download C4000BG firmware

Download C4000BZ firmware

Download C4000LG firmware

Download C4000LZ firmware

Download C4000XG firmware

Tip: If the firmware link doesn't work, try another browser (Chrome is known to have issues with this kind of link). Or, right-click the link, select "copy link address", then paste the link into a new browser tab.

Video: How to control your C4000 wireless settings

Need more WiFi? If you need to boost or extend your signal, consider ordering a WiFi extender from our Accessories shop, in the WiFi Performance area.

Starting new service? Please note that a phone jack is required to set up CenturyLink internet service in your home. If you don't have a jack, chat with us to have one installed.

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