Configuring the CenturyLink Actiontec C1000A modem

Configuring the CenturyLink Actiontec C1000A modem

File this one under the “I wish I’d known about this a long time ago” label. Yes, it’s one of those rabbit holes you jump down thinking it’s dead simple and quick, and then spend some inordinate amount of time and sweat following what turns out to be just one dead end after another.

First things first. I now take my Dell XPS 12 with me on trips and leave my heavier (those two extra pounds now really make themselves felt) Dell XPS 15z at home, humming away. Unfortunately, every now and then I wish I had access to some feature or document on the 15z when I’m away travelling. And of course it just remains there well out of reach, with my memory and imagination pulling up the app’s window or the File Explorer listing in my mind’s eye.

So, today – I love these quieter days between Christmas and New Year’s – I decided to set up Remote Desktop Connection for the 15z and to configure my CenturyLink DSL modem and my home network router to allow Remote Desktop connections to be passed through. Here’s a figure that shows my home network configuration:

Idealized Home Network

Why do I have two routers? Well, CenturyLink insist on the Actiontec C1000A modem being the entry point from their DSL line to our home network. It came with the data speed plan I selected, essentially, so I’m stuck with it. I have a couple of wired devices running off it, but in essence it’s a gatekeeper to the Asus RT-N66U router that is the main workhorse of our network. It is this latter router that provides our wireless capabilities and the 15z is wired directly to it with a 1Gbps connection.

So, in order to provide Remote Desktop functionality when I travel, I need a fixed endpoint from the internet (I have a static IP address) and then the modem and the router must both pass though the Remote Desktop connection. In other words, the Actiontec must forward the 3389 port (this is the Remote Desktop port) to the Asus, and the Asus must, in turn, forward the 3389 port to the 15z.

Easy peasy, you might say. Just log into the configuration pages for the modem and the router and set it up. The local IP address of the Asus router from the modem is provided by those same configuration pages, and ditto for the 15z’s local IP address from the Asus router. Except that no matter how hard I tried, when I clicked the Apply button in the configuration page, it would not ‘take’.

ActionTec modem: apply Port Forwarding

This was nuts: I’d check the list and the new port forwarding didn’t appear, I’d set up the exact same data as shown, click Apply, and it would not save. Oh, don’t get me wrong, the modem would display a message for several seconds saying that it was applying the changes , but at the end there was no new port forwarding item. My first thought was that maybe the changes had to be applied from a PC connected directly to the modem – I was doing this from the 15z itself through the router. Out came another laptop (the XPS 12 as it happens), I turned on the WiFi on the Actiontec modem, and… exactly the same result. Big fail. Time for Google. Even then, it took a while to find a small hint buried deep in some forum thread: use Internet Explorer. I use Firefox by default and Chrome in times of trouble or for a change. I never use IE; I dislike it thoroughly. But this time I started it up, and the modem configuration pages worked just fine: the new port forwarding item was saved as advertised.

Compared to this, the configuration of the Asus was a breeze. Finally I tested the Remote Connection by using the XPS 12 connected to the Personal Hotspot from my phone. It worked, albeit a little slowly on LTE, but, then again, this is not how I shall be using it.

So the moral of this tale is: If you are configuring an Actiontec C1000A modem provided by CenturyLink, use Internet Explorer.

(Aside: so I started to browse the JavaScript the modem emits. Let’s just say I saw “jQuery 1.3” and decided to let it go. There are only so many hours in the day.)

Album cover for The George Benson CollectionNow playing:
Benson, George - White Rabbit
(from The George Benson Collection)

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11 Responses

#1 Kevin Taberski said...
05-Jan-14 10:24 PM


I'm having a heck of a time configuring an Actiontec C1000A to port forward to an HTTP Server.

Previously, I was using bridged mode (with an Actiontec M1000), but my ISP switched me to PPPoA (at which time I switched to a C1000A). So I know everything worked prior. I was using a Linksys WRT-54GL running DD-WRT (which I'd prefer to continue to do), but now I'd be almost happy if I just got anything to work.

It seems at though this should just work. I was wondering if there was anything else you had to do other than forward the port of interest? Are you using the C1000A as your DHCP Server or just a modem?

Any insight is greatly appreciated,


julian m bucknall avatar
#2 julian m bucknall said...
09-Jan-14 9:38 AM

Kevin: I actually use port forwarding with the C1000A to forward port 80 to an 'experimental' web server I have at home. It all works fine, and I don't remember having to do anything special to set it up. (Actually, looking at it, I used the Applications Forwarding page to set this up, same difference.) So the C1000A does act as a DHCP server since it provides the IP address to the web server. I also have a VOIP phone on that modem too, and for that one I had to configure it to forward a couple of ports.

Sorry, I can't be of more help...

Cheers, Julian

#3 Mohy Eid said...
10-Feb-15 5:29 PM

Kevin, did you solve your issue? I have spent couple of nights to make this work. I enabled DMZ and disabled firewall. Also enabled remote GUI all my port forwarding looks good and no luck. I called century link and stayed them for an hour to convince them that my wireless is working and that I need port forwarding to work, but their knowledge is limited to fix my wireless :). Please, help.

#4 Wanda T said...
02-Mar-15 8:24 PM

Just want to thank you, been fighting with CenturyLink Internet service for three days (just basic "reliable" service) on my third modem, finally insisted on something other than the Zytel crap they kept giving me. Could not change the log in under quick set up - found your note here and voila, as soon as I used IE instead of Chrome problem solved - thank you for taking the time to post for others.

julian m bucknall avatar
#5 julian m bucknall said...
02-Mar-15 8:57 PM

Wanda: Glad to be of service!

Cheers, Julian

#6 Del Quent said...
05-Mar-15 5:32 PM

so both the Asus and the actiontec are Wi-Fi access points?

can they have different ssid's?

I need port blocking, and it's not on the actiontec. I could plug a router into it, and use that for port blocking. but if they're the same ssid, and the actiontec is still providing Wi-Fi, my kids could still just as easily connect to that.

julian m bucknall avatar
#7 julian m bucknall said...
05-Mar-15 6:02 PM

@Del: Yes, but I only use the CenturyLink router's WiFi (the one closest to the Internet) for guests -- it's off most of the time. They can't access the Asus router because of the firewall in between, and hence can't 'see' all our PCs and devices. Although I'm confident that our PCs are up to date OS and browser-wise, well-protected, and malware/virus-free, I can't say the same for my guests, unfortunately. So, better safe than sorry.

Cheers, Julian

#8 Tony McIlroy said...
01-Jun-15 9:51 AM

I lease a c1000a modem from dishnet. I would like to buy this modem from someone and return theirs since they will sell it to me. Are their modems propietary or will any c1000a work?

#9 Martin said...
01-Oct-15 9:55 PM

gui remote axss in action tech c1000a i cant axcess the modem remotely by no means. I have gui enable and set up in port 443. please help

julian m bucknall avatar
#10 julian m bucknall said...
02-Oct-15 7:21 AM

@Martin: Can't help you I'm afraid. There's no way I trust a router's software enough to enable remote GUI access. After all, it's rare that they're updated to fix security issues. I'd rather keep them as locked down as possible.

Cheers, Julian

#11 DannyC said...
16-Jan-16 4:59 PM

Using IE. Been at it 9+ hours with my C1000a to either application-forward or port-forward to an Apache webserver that is working fine on the internal network. Just need to vent. I've got zip, zilch, zero, nada, nothing, bupkis, naught, nix.

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