Setting up a 3G Modem with a ZyWALL USG Firewall

While attending the IT Connect conference in May I was introduced to a line of firewalls from ZyXEL.  I had actually heard about them before and even wrote a little about the content filtering option in a previous post.  However, it is a different thing to have read about a device and to have somebody who knows the ins and outs of it take you through each configuration page and show you what it can do (thanks Marcelo).  That is why I can say that I was “introduced” to it in May.

I was impressed enough with the capabilities that I decided to buy one for use at home.  I was in the market for a 3G router and was interested in purchasing a device that I could also recommend to others.  For my own purposes the ZyWALL USG 20W fit my needs quite well.  Actually, this is really an enterprise level device so it is way more than I need.  But I do think it will be good for small offices, and the best way to be able to support something is to use it myself.

The first task that I had when I received it was to connect it to our 3G internet connection.  (Perhaps at some point in the future I will write a review of the device, but for now I am going to tackle this single issue.)  I will note that the IT department bought a USG 50 about a year ago and tried to use a 3G USB modem as a backup internet connection for our guest house, but could never get the connection to go faster than EDGE.  At the time I did not have access to experts and so just assumed it had something to do with the connection in Ghana and the modem that we had chosen.  Since that time ZyXEL has increased the number of modems that work with the ZyWALL’s, so I had more hope of getting beyond this issue.  I verified that the modem that I wanted to use was listed as supported before I made the purchase.

As soon as I unboxed the router I quickly set it up and connected into the admin screen, excited with my new toy.  Um, I mean sophisticated piece of equipment for work.  I plugged my Huawei E173 modem in and went into the cellular configuration screen. It was quickly recognized as a Huawei Generic Card.  The APN and connection settings were read automatically from the ISP, so when I clicked on connect it worked right away.  I started to load a website, but it was very slow.

I went to the cellular monitor screen.  It showed that I had a signal, but it was weak.  That did not surprise me as that was normally the case where I was doing the testing.  To my horror though the connection showed EDGE!  It was the same problem all over again.  This time I had done my research, so I was not sure what the problem could be.  The modem was one that I had been using for a couple of years, so I knew that it could handle a faster connection.  I went back to the ZyXEL’s list of supported 3G modems, and sure enough, there was my modem.  Then I noticed something that I had not paid much attention to before.  Next to each modem, and some modems were listed twice, there was a specific firmware that was supported.  It was not difficult to confirm that my modem did not meet the requirement.

Supported modems with firmware
Supported modems with firmware

After some research online I found out how to update the firmware of my modem.  I was able to download the new firmware from After the update I plugged the modem back into the firewall, checked the status page, and too quickly started rejoicing when I saw that it now showed the connection as WCDMA.  I went back to the configuration page and told it to connect to the internet.  It did a lot of spinning and counting to 60, but no matter how many times I told it to connect it always timed out.

I went back to the ZyXEL site and this time downloaded an update to the firmware for the router.  My device was brand new and the firmware was not really that old.  In fact, it took me a little while before realizing that there actually was a newer version.  After downloading and installing it I still had the same problem.  The router saw the modem, the modem saw the WCDMA connection, but would not connect.  I then proceeded to move the equipment all over the house thinking that perhaps my problem was the weak signal.  You should have seen how I stacked furniture to get the modem in just the right location.

After going through all of the configuration settings again I finally found my problem.  Apparently when I flashed the firmware for the modem, even though it kept the setup files from the ISP, it no longer automatically set the APN and Dial String.  I changed that to custom, put in the correct settings, and all was well.

Custom connection settings
Custom connection settings

There are two frustrations with the ZyWALL that I think would be easily solved.  First, the cellular configuration and status screens are in two different places on the admin screen.  It takes four or five clicks to get between them.  That would normally not be a problem, but when you are troubleshooting it becomes extremely annoying.  Second, it should be more obvious that there are different versions of the firmware.  For example, my firewall came with version 3.00(BDR.0) and the updated version was 3.00(BDR.4).  It would have been far more obvious if they had changed from 3.00 to 3.04 or something like that.

Success! WCDMA connection and updated modem firmware
Success! WCDMA connection and updated modem firmware


Update June 2016:

This post continues to get a lot of hits, so I wanted to give a quick update on my experience with the ZyXel USG 40.  Although ZyXel continues to maintain and update the firmware on the USG 20/20W/50 series, it has not added support for newer USB modems.  The newer USG 40/40W/60 devices offer a much more expanded list and so we decided to go with the USG 40 for a new installation.

Unfortunately so far I have not had very good experience with the USG 40.  This last week I tried to use both a Huawei E3131s-1 and E303s-1, and failed on both.  The E3131 is recognized as an E303/E3131 (CDC-ECM). It says that it is connected, but both the Service Provider and Signal Quality are n/a. The E303 is recognized as E398/E3276 LTE/UMTS/GSM Modem. It sees the service provider correctly and has excellent signal. But for the status it says “PPP Fail.”

ZyXel provides a list of USB dongles that are supported by the firewall.  It contains both an E303 and E303s-2, but not the E303s-1, so I can kind of understand why it does not work.  But the E3131s-1 is specifically listed.  I have submitted a report to ZyXel about the issue and hope to hear back from them.

For now the good news is that Huawei E173 with updated firmware as explained above does work with the USG 40.  Unfortunately they are really hard to find.  We were lucky enough to have somebody come into the office with a support question who happened to have one, so we traded them a new modem for their old one.

Note that the firmware of the USG 40 is updated to V4.15(AALA.2).  The Dongle support update is 1.06.



8 thoughts on “Setting up a 3G Modem with a ZyWALL USG Firewall

  1. Hi! I have a ZyWall USG 20 and a Huawei E173 both with the latest firmware. The E173 works perfectly on 900MHz 3G when I connect it to my laptop, but when connected to ZyWall I only get EDGE. When I move my equipment to a place where 2100MHz 3G is available, I get 3G also when the E173 is connected to the ZyWall. Can it be so that for some odd reason I can’t use 900MHz frequency when using E173’s internet via ZyWall? Thanks!

    1. My guess is that there should not be a difference in how it handles the frequencies, that would be an issue in the modem or configuration. From what I can tell I am on 900MHz here on the E173. There are two things that I would check. First, see how strong of a signal you are getting when using it on your laptop. If it is weak, that could be the issue. Second, check that there is no difference in your configuration (for example APN) between the 2100 MHz and the 900MHz services.

      1. Hi and thank you for a quick reply! On my laptop, the E173 receives “very good” signal on 900MHz. I’m using the same APN & Dial String configuration on both the ZyWall and my laptop so it shouldn’t be due to that either – all configurations are the same. It may connect to 3G for a couple of seconds (my guess is there is a very weak 2100MHz connection available and it tries to connect to that) but then it returns to EDGE. I’m so confused :O

      2. I wish I had an answer for you, but really not sure. My understanding is that ZyXel support is pretty good, so you want to try contacting them about it.

  2. 1.
    I might be a bit late, but the USG series has an option, under \configuration\network\interface\cellular\ edit the cellular settings to accept only edge or cdma/umts. that can solve some of the issues. i used to have that problem when i had a poor 3g connection, it was a bit flakey, due to the location, i could not move my USG anymore, but it solved the issues.

    2. ALWAYS important to know: the device will try and use the strongest signal, as this makes for better throughput, even at lower speeds, i know its hard when a whole office depends on it, but any modem will do that, as the software is built that way.

    Another thing that can come in handy if you have a good signal in one place and the device is elsewhere, you could try using one of these:

    Basically it makes a long usb cable, without the need to put boosters in between. they claim 60 meters, about 180 feet, but i have not gotten it to work for more than 10 meters, 30 feet, but i did not buy a high quality one, just the cheapest one i could find to test with.

    3g support, one issue we faced with an ISP where i live is that they don’t have a password for the authentication, but they do have a user name, the GUI does not allow you to not have a password, so some CLI can solve that.

    Anyway, just some thoughts.
    There is also a new Firmware out, the ZLD 3.30 with a few revisions. you can check the site search for the model number you have and you should be able to get the firmware you need.

    Hope this helps.

    1. Hi and thank you for your help! Even though I choose “use only UMTS” from advanced settings, ZyWALL will connect to EDGE only. I already have an external antenna connected to the dongle and I tried to find better signal with it outside the building with no success. I also double checked that my ISP doesn’t use either username or password for authentication. I have the latest firmware as well. I’m waiting for ZyXEL support people to reply but apparently they won’t. A random idea crossed my mind: Is it possible that the USB port is not powerfull enough and purchasing a powered USB hub would solve the problem? I don’t think so as it connected to 2100MHz in another location but at this point even the dumbest idea seems clever you know 🙂

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