Saturday, September 2, 2017

ZYXEL C1100Z DSL Modem Setup

How To:  Manually setup a Zyxel C1100Z DSL vDSL Modem

Setting up a DSL modem/router is easy.  You can follow the vendor's installation steps, which sometimes require installing software or connecting to a setup-website or you can follow the steps in this article.

These steps are more complete than the vendor's and will take about 20 minutes to complete.  Almost all DSL routers and cable routers follow similar procedures.  Use these instructions for new or re-configured devices.

Note: The instructions in this article should be used when the DSL router has multiple workstation ports (1-4). If your DSL modem has only 1 (yellow) port, see the EA2700 article, below.

Related article:
Keyliner: Linksys EA2700 Wireless Router - First Time Setup

Your setup may not have optional devices.  However, I recommend using a separate wireless router because it has more capabilities and speeds than the wireless built into the DSL:

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Basic Setup

1.  Wire the network in this fashion:

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a.  Plug the green RJ11 phone cable into the phone-wall jack. 

Plug the other end of the green RJ11 phone cable into the new DSL modem's "green" port.
Do not use a DSL line filter or DSL line dongle on the green line.

b.  Plug a (yellow) RJ45 network cable into any one of the four yellow ports, and plug the other end into your desktop or laptop's wired network jack.  This is a temporary connection for the setup.

If your workstation does not have a wired network jack, use the DSL modem's wireless for the setup, but this is not recommended.  It is easier to use a wired connection and the rest of the article assumes this.

c.  Connect the Router's power.

While the router is powering-on, do the following on your workstation or laptop:

-  Assuming you are using a wired connection: turn off your workstation's wireless antenna (especially if using a laptop.  Desktops may or may not use a wireless connection). 
See the system tray; click "Wi-fi" to disable. This forces the workstation to connect to the wired network.

- If you are using the DSL modem's wireless to configure the network, use the broadcast SSID and password printed on the side of the modem.

d.  Reboot your workstation to obtain a new IP address.

Note:  Your workstation will probably get an IP Address of

2.  Get the DSL Login credentials

From when the DSL line was first installed, you will need the DSL login credentials. This is the DSL circuit-login and is not the computer's login or any other login normally typed.  Usually, this is on a letter mailed to the house and is labeled PPP or PPPop login information.  If you have this, skip to step 3.
If you do not have the login credentials, continue

a. When rebooted, launch a browser and (at least with Century Link), the router will take you to a site, offering to login.  Using a recent phone bill, login with your ISP's account number and go through other screens to prove your identity.  Once you succeed, Century Link will display your DSL credentials.  Record the values; you will need them below.  Naturally, logins are case-sensitive.

If you still cannot find your DSL PPP login, contact your ISP.

Century Link / Qwest: 877.348.9005 or 888.777.9569
ATT 877.722.3755
Verizon 800.567.6789

Continue with the Setup

If you launched a browser (with CenturyLink), it will take you to a website, where you can follow the instructions on how to setup your modem.  Although the offered instructions are good, it does not actually do anything to your router -- the site is essentially an electronic tutorial and can be ignored in favor of these steps.

3.  Assuming you have rebooted the workstation, launch a browser and type this address:

You should be presented with this login page:

Type Administrator UserName:  "admin"
Type Administrator Password:  (see sticker/label on side of modem)

The UserID and password are case-sensitive.

If you do not get this login screen, confirm the yellow network cable is in one of the DSL Router's yellow ports - and not in the LAN/WAN port.  (Or, if you are using a wireless connection, confirm you connected to the wireless network printed on the router's label.)

Bad Password:  If you cannot login because of a bad password, the modem has a different password than sent from the factory (you would have done this previously). If the password is lost, the modem can be factory-reset by powering on the modem, using a paper-clip to press and hold the Reset button for 10 seconds.  Release the reset button, wait a minute, then try the login again.

4.  From the Zyxel main menu, select Quick Setup.

From step 2, type the DSL circuit login credentials. 
Your domain may be different than illustrated.
PPP Username:  *****
PPP Password

(uncheck [ ] Hide password; keeping you from having to type the password twice)

Change the "Custom Realm" pull-down menu, changing to your ISP's domain name.  For example, mine was changed to ""; yours may be "@CenturyLink", etc.  If your domain is not listed, leave as "Custom".

Click "Apply"

5. In "Advanced Setup", change the Administrator Password,

Recommended:  Change the administrator password to something you will remember.  The password must have upper and lower-case, a number, and a special-character -- which is odd, because the factory password is not so-restricted.

Consider this keyliner article: Password Schemes.  

Record the new password on the modem's label, and in your login documentation.  If you lose this password, you have to re-do all of these steps to recover.

6.  In the "Utilities" menu, click "Upgrade Firmware".

Follow the on-screen instructions.  You will basically download a firmware file, browse to it, and apply.  This is recommended.

As of 2017.09.01, Zyxel C1100Z's latest firmware is CZW0034.12.010.16.
If your version is older, it should be upgraded.  Return to this menu once or twice a year for upgrades.

7.  In the "Utilities" menu, set the Time-zone and Daylight Savings Time.

8.  Configure Wireless settings - even if you intend to disable this device's wireless.  This way, if you ever need to enable this part of the network, it will be pre-configured and ready to use.

In the "Wireless Setup" menu, set a new SSID broadcast name.

Change the network SSID name from "CenturyLinkxxxx" to a name of your choosing.  For example, my network is called "WolfhouseDSL".

If you have another, downstream wireless router, this name cannot be the same as the other router's SSID.  I append "DSL" here so I can tell the two apart.

Change the WPS PIN to a value you will remember.  Write this down.  This is used for automatic workstation setup, which some people like to use.

In "Wireless Security", change the Security Key/Passphrase to a string your will remember (this is the connection/passphrase for people to log into the wireless network).  Make sure this password is different than your Admin password.  Make it memorable.  For example, I use "wolfy DSL 1979".

Record this in your documentation.

9.  Decision:

If you have a second, wireless router (illustrated as, let that router handle the wireless traffic and disable the DSL modem's wireless.  I call this second router a "downstream router" and it will be faster and more capable than the wireless built into the DSL modem. This is recommended.

Because the DSL modem has 1-4 available ports, the downstream router will have special setup steps, documented in the next section. 

Caution:  If you are using Wireless to configure the DSL router, leave the wireless enabled until you are done with all configuration steps.  

If you are using a wired connection right now (to setup this network), and have a second, downstream wireless router, disable the Zyxel's Wireless now.  In the top-menu, "Wireless Setup," click "Disable"

Even if the Zyxel's Wireless is turned off, you can still connect wired desktops and laptops to the four yellow ports.

10.  Change the DHCP address range

Make this recommended change, moving the Zyxel's DHCP address pool from .2  to .10 -- giving room for other routers and hard-coded devices.

In the top-menu, Advanced Setup, choose the left-nav, "DHCP Settings"

Change the "Beginning DHCP address" from  to
Change the "Ending DHCP address" from     to

Optionally: I like to set the Lease Time to 3 days, although the 1-day default is acceptable.

"Apply" the changes.

The router is now configured and ready for use.

Secondary Wireless Router Wiring Changes

If you have a secondary wireless router (illustrated above as, do these wiring steps.  These steps will place all devices on the same subnet and the steps are a bit counter-intuitive.  Skip this entire section if you do not have a downstream router.

In summary, change the wireless router's IP address to a Static "" address, then disable DHCP.  This is a one-time setup, just to get the new router on the proper network.

The steps vary by manufacturer, but in general:

a.  Unplug the wireless router from all other network wires.

b.  Plug your workstation's wired Ethernet cable into any yellow-port on the wireless router (similar to how you connected to the Zyxel DSL router).  Or use wireless to connect to this device; see the owner's manual for the default SSID broadcast name. 

c.  Reboot your workstation to get a new IP Address.

d.  With a browser, login to the wireless router's admin page, using the default router's address.  See the router's owner's manual, but usually:  or

Login with (the published default password).  For example, see this article for more detailed instructions:
Keyliner: Linksys EA2700 Wireless Router - First Time Setup

e.  In the advanced settings [Local Network], disable DHCP

This is important: Do not allow this router to give out IP addresses; this will conflict with the Zyxel -- even if you pick a different DHCP range.

f.  In Connectivity, "Internet Settings," set the router's internal IP Address to a hard-coded (Static) IP address:

Static IP:
Subnet Mask:
Default Gateway:
DNS 1:  

where  "0.2" is on the same network as the DSL router (the third octet)

where .2 is below the DSL's router's starting DHCP Address Range  (which was moved to .10 - .100) in step 10, above.

where  is the same IP Address as the Zyxel DSL router

where DNS1 is "".  This is Google's DNS server - as good of an address as any.  Your ISP would prefer you use their DNS server, but Google's is safer.   (Some ISP's slip-stream their own content into data-streams.)

Apply the changes.  When you do, you will temporarily loose connectivity to the router.
Continue with the next steps.

g.  Power off the downstream router.

Then, run a network cable from one of the DSL router's 1-4 ports, into the downstream router's 1-4 ports -- any port, on either side will work (illustrated above with a yellow cable).  Do not use either of the WAN/LAN ports -- you want this router to be on the same network as the main DSL router, and because of this, you cannot use the WAN/LAN ports.

h.  Move your workstation's Ethernet cable to any free-port (yellow) port, on either device.  I like to move the cable back to the DSL modem's 1-4 ports.  Again, avoid the white WAN/LAN ports.

i.  Again, reboot the workstation to get a new IP Address.  Yes, this is a drag.

j.  Once connected, open the browser and type this IP Address: (the downstream Wireless Router's address) -- and again, login to the router's admin pages.  (Note: you can now also login to the DSL's router's admin by using the 0.1 address.)

Make these additional changes (see the Linksys article for more details):

- Set a memorable SSID -- make this different than the DSL's SSID -- example: Wolfhouse5G
- Set a Network password (for wireless access):  wolfy house 5G
- If the router has a second channel (e.g. 2.4ghz), SSID:  Wolfhouse24G
- Set a second password (for wireless access):  wolfy house 24G

If the router supports a third channel Guest network (most do):
- Set the SSID broadcast to "Wolfhouse Guest"
- Set the guest password (for wireless access): wolfy house guest

k.  Finally, change the Router's (admin) password, to a value of your choosing.  Write this down.

The wireless router's setup is complete.

Optional Switch

If you have an optional 8-port switch, illustrated above, do the following.

- Run a (yellow) network cable from any of the yellow 1-4 ports on the DSL modem to any yellow 1-8 port on the switch.  Do not use the WAN/LAN ports.  For minor performance reasons, you should not run the network cable from the downstream wireless to the switch; instead, go directly to the DSL modem's 1-4 ports.

-power-on the switch; you are done.  No software configuration required.

Analog Devices

If you have a land-line phone, the phone can be plugged into the Zyxel's phone jack and no DSL filter is required for this connection.  If you have other analog phones or analog phone devices, such as phone-based alarm systems, satellite receivers, answering machines, etc., you must use a DSL line filter on each of those jacks.  These will have to be purchased separately and can be found anywhere analog phones are sold. 

Printers, TVs

With printers and an internet-connected TV, I recommend running wired Cat-5 network cables.

If you can, run a wired connection for the printer; it is less of a hassle -- many printers (especially Brother printers) dislike it when the wireless router moves to a different channel after a power failure.  A wired connection prevents these types of problems.

Related article:  Keyliner Brother Wireless printer fails after power failure.

And, because of DHCP, printers tend to move around and get new IP addresses when they reboot.  This is a pain and it forces you to re-build printer connections at each workstation.  Regardless if wired or wireless, set the printer to a fixed or static IP address.  From the printer's main panel, set a hard-coded IP Address.  I like to use these settings:

Static IP Address:
Subnet Mask:

Default Gateway:

where 192.168.0  is the same network as the Zyxel DSL router.
where .200 is an address outside of the DSL Router's DHCP range.
where is the Zyxel's IP Address

Similarly, I also set the TV/Roku to a fixed address:  (keeping the number below .254).  Because it is such a high-bandwidth device, the TV should be on the wired network.  I always smile at people who buy a 100mb high-speed network connection for their house and then run the TV over a 10mb wireless network.


Sometimes, after a power failure, these routers loose their gourds and have to be re-configured.  Save yourself the hassle and buy a small battery-backup UPS for the network devices.  Plug the DSL modem and downstream routers and switches into the UPS.  Make this separate from the PC's UPS.

Most UPS's have two sides:  A battery-protected side and a simpler surge-protection side.  Be sure to use the battery side.

When powering on the network.  Power-on the DSL modem first.  Wait a minute, then power on the other devices.

Final Network Test

From any workstation, wired or wireless, running on the new network, open a browser and make one last connection to the new Zyxel router:

Login with your new admin credentials and confirm you can reach the configuration menus.  You should be successful. Then open a browser session to something like  The page should display.

If you have a downstream wireless router (illustrated above), now would be a good time to turn off the Zyxel's internal wireless.  From any workstation, return to the's configuration screens and disable.

Using any workstation, confirm you can get to the downstream wireless router's admin screen by typing this address:

If all this works, you are golden.

Record Keeping

It is embarrassing and painful to lose your router's passwords.
Write this information in a safe place because if the Internet is down, you can't exactly jump on the net to find your contact information.  Don't wait to do this because you will forget.

ISP Name: ______________________________________________

ISP Technical Support Number: _____________________________

DSL PPP Login Credentials: _________________ /  _____________

DSL/ISP Account Number: _________________________________
(Often the home phone number.  If no home phone, see bill for separate account number)

DSL Modem Model Number: _______________________________

DSL Modem IP Address: ________________________

DSL Modem Admin Login:  admin / __________________________

DSL Wireless SSID Broadcast Name: _________________________ [  ] Disabled

DSL Wireless SSID Password: _______________________________ [  ] Disabled

Downstream Wireless Model Number: _________________________

Downstream Wireless Router IP Address: ____________
(Optional, if you have a separate Wireless router; see below)

Downstream Wireless 5G SSID: ______________________________

5G Password: _____________________________________________

24G SSID: _______________________________________________

24G Password: ____________________________________________

Guest SSID:  ______________________________________________

Guest SSID Password: _______________________________________

Printer IP Address:  _________________________________________

Related articles:
Reset Linksys Wireless Password
Linksys EA2700 Router First Time Setup
Installing a NetGear DM111PSP ADSL Modem

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