3CX on Azure is the Cloud Ready for PBX?

Posted by:

3CX on Azure Maybe the Standalone Version

As an entrepreneur in the IT Industry I am always looking for new opportunities in IT. Is 3CX on Azure one of those opportunities? Our company, Austen Consultants is always on the hunt for new streams of revenue. It became apparent that VOIP is finally becoming affordable for everyone; the competitors like Cisco and the days of a 50,000 dollar investment to obtain an Enterprise IP PBX are over.

We first came across 3CX while doing research for a school district. A simple Google search for IP PBX and there it was…3CX. They were one of the first to come up in the search and within days we had a POC and shortly after, were signed up as a reseller and had our NFR Keys. I will go into more about this in another blog post. For now let’s talk about how and why we tested 3CX on Azure and vCloud Air.

3CX on Azure

Our company is a Microsoft Partner as well and use Microsoft Action Pack so we get $200 a month credits on Azure, perfect for a test bed for things such as a 3CX PBX in the cloud. After spinning up a 2012R2 VM and installing the standalone version of 3CX, we were able to start our testing. With a single instance, the results were positive, we could make calls and everything else appeared to be working on Azure. We connected Azure via VPN back to our Data Center in North Texas. We used an ASA 5505 and a few public IP addresses and via a Yealink T48G, we were making calls.

We tested Appia and Flowroute on Azure and we routed that voice traffic for SIP through the VPN connection. The VOIP carriers were connected on our Internet facing firewall and routed to Azure and our VM. Call quality was fine and for a company I think with enough bandwidth, a stable connection (we use Gigabit Ethernet from our provider) and a nice firewall I think the results would be a good or better than expected outcome.

If you are a company that wants to keep expenses down and pay as you go this might be a good fit for you. Since we are a hosted voice provider it doesn’t make sense for us to have a server for each customer. The prices for the bandwidth, server time and hard drive space would be to unpredictable leading to a huge bill from Microsoft.

Anyway, if you are interested in hosting a VOIP PBX it will not work on Azure using the 3CX Virtual PBX, here’s why. Using the 3CX virtual PBX requires that you have one server with up to 25 instances or customers. This server has one to one NAT with one public IP address. So here’s the catch, based on that previous statement each instance has it’s own unique port numbers, for instance.

  • Customer 1 uses port 13060 for SIP and 13090 for the 3CX Windows phone tunnel
  • Customer 2 uses port 12060 for SIP and 12090 for the 3CX Windows phone tunnel
  • RTP Ports

Therefore connecting via ASA to Azure on a VPN listening for these ports does not traverse NAT well and it hates the VPN connection, also known as hair pinning. The audio suffers, the connection drops out and the configuration that would be needed is not worth the expense and effort. You can’t use Azure directly because you can’t open enough or forward ports through their firewall. So in my humble opinion Azure is out on the list as of now to use as a hosted platform for the 3CX Virtual PBX.

It made sense to us, as we would not have to invest in hardware and could use a pay as you go model and be up and running with little or no upfront costs. However, it’s just not there yet for a Hosted IP PBX provider like us. It is also not supported by 3CX. The standalone version is not as well as of this writing.

We ended up building out our own infrastructure at our data center using Cisco, Dell and vmWare as are hosting platform. This helps us figure our costs exactly with no guesswork and is a highly available platform to host our 3CX Virtual PBX. If you are interested in a hosted business phone system contact us and we would be happy to put you on our Hosted PBX our help you design and architect your own.



  1. power washing ct  July 13, 2016

    I enjoy the efforts you have put in this, regards for all the
    great articles.

  2. Larry  October 13, 2016

    Good info…poor grammar 🙁

    • admin  December 2, 2016

      Well I am from the south so I tend to type like I talk. Thanks for the useless information!

  3. Adam Comben  October 24, 2016

    Good afternoon, great article – I can’t help thinking that you ought to be deploying 3CX SBC’s on-site to alleviate the port issues? This communicates all SIP traffic over a single port, side-stepping the large number of ports to be open. Is this something you explored? All remote deployments we use SBC’s and they work fantastically!

    • admin  December 2, 2016

      They don’t work if you have more than 16 phones.

  4. Ricky  January 20, 2017

    Good post but I was wondering if you could write a litte more on this topic?

    I’d be very thankful if you could elaborate a little bit more.

    Thank you!

    • Matt Ussery  February 24, 2017


      I just did an update about 3CX on Azure, take a look.

  5. Franklin  January 23, 2017

    Appreciate this post. Will try it out.

  6. corburt erilio  February 11, 2017

    Hi there! This post couldn’t be written any better! Reading through this post reminds me of my previous room mate! He always kept talking about this. I will forward this article to him. Pretty sure he will have a good read. Thank you for sharing!

  7. IveyQTrigg  May 30, 2020

    Thanks , I have recently been looking for information approximately this topic for a while and yours is the best I have discovered till now. However, what in regards to the conclusion? Are you positive concerning the source?

  8. HermilaCToye  May 31, 2020

    We stumbled right here by a different website and thought I may too check things out. I enjoy what I see so i am just following you. Look ahead to exploring your online page repeatedly.

  9. LiaGHighnote  June 1, 2020

    A person essentially assist to produce seriously articles I’d state. That may be the first time I frequented your website page and up to now? I amazed together with the analysis you intended to create this actual submit amazing. Fantastic job!


Add a Comment