Free open source SIP trunk

Currently I am following a video series to configure freepbx. In this video it shows how to configure outbound routes and it is using flowroute as SIP trunk.

I would like to know if I can use my own SIP trunk. I mean open source which I can configure on my own server?

Has anybody tried open source SIP trunks and what was the experience?

Note: I want to create a VOIP setup which is by all means completely built without using external services.

I’m afraid you don’t completely understand the concept of a SIP Trunk.

Look at it like a network, you have your local machines/devices on your network with a domain and local DNS server and then you have a gateway which allows you to access machines on the internet.
How does it work? When you try to go to your DNS server can route them to the local mail server, but what if is in the cloud? Your computer will go out to the internet through the gateway and find the server.
Now, if you remove the gateway, will you still be able to access a local server? Yes.

Same is with a Trunk it’s a gateway, you dial extension 101, your PBX will try to find a local extension, if it does not find it locally it’ll try to look if there’s an outbound route which allows the PBX to route that call through a Trunk.

So when you dial 8881115555 your PBX will not find any local extension, so it’ll try to route to a matching outbound route and then the Trunk.

And for that Trunk you need a provider which will accept your calls and connects it with the outside world.
And every provider is charging money (besides Google Voice)

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Sure. You could configure two FreePBX servers independently and then set up a SIP trunk between the two of them. The exercise will let you experiment with trunks and inbound/outbound routes.

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Thank you for a detailed answer.

Is it very expensive to create my own service like google voice? I mean becoming a provider.

I was searching and found these. and

Not completely sure what are those. Thought you might have an idea. Also when searching for alternatives of flowroute, I saw skype for business as an alternative trunk.

I think you are confusing the concept of a ‘trunk’, which is simply a connection between two switches, and the services delivered over the trunk, such as the ability to call a PSTN number or send a fax.

You also may be confusing free speech with free beer. For example is a very large scale communication platform that is entirely open source. However, its pieces are connected via the internet, so cellular carriers, ISPs, etc. must be paid to make it work.

You could construct a system with numerous FreePBX instances interconnected with Kamailio or similar, but it would probably have the same constraints as Signal. Smaller ones might be able to avoid paid carriers, e.g. university-owned fiber covering their campus, or a neighborhood system using Wi-Fi links.

Becoming a ‘generic’ VoIP provider is IMO total insanity – competition is cutthroat, fraud is rampant and regulatory issues are a nightmare. However, if you have something significant to bring to the party, a specialty service might make sense.

Becoming a nationwide carrier such as Bandwidth or Intelliquent would cost billions. For a few million, you can be a carrier in a few major cities, like the providers Callcentric and Voxbeam.

However, most VoSPs are not carriers at all; they buy numbers and minutes from carriers and resell at a markup. The really small ones can’t justify the minimum commitments that the carriers require, so purchase from wholesalers such as AnveoDirect and ThinQ.


And well understanding the actual industry. It’s one thing to sell PBX systems and slap a trunk/peer to some ITSP out there. It’s a completely different beast to just become a provider. Every country has their rules and regulations that need to be followed or adhered to. You need to understand how the PSTN works, how carriers interconnect or interact with each other. How DIDs and other things are properly handled, routed, et al.

Having FreePBX/Asterisk, some billing software and a Flowroute account doesn’t make you a provider. It makes you someone that just has the same setup as every ITSP in a Box TM has and nothing is an actual voice product or service. It’s just “What can I do with FreePBX, that’s the stuff I’ll provide”. That in no way is not being a provider.

This is what I do for a living and all I even see these days are people taking their ITSP in a Box TM kits and trying to be a provider. Sure everything is all fine setting things up and getting them going but it all crashes and burns when things are not in the instructions or behaving like it should. Sooooo many come in here and on IRC with the “How do I do this?”, “Can I do this in X module?” or “My customer is having problems and I don’t know what it is, can you help?” and the moment you try to help them you get “I don’t understand. I don’t know what that is. etc., etc., etc.”

Telephone service is considered a Public Utility and thus has a level of expectation for it. Most of these kit users couldn’t meet or understand that level of expectation if it slapped them in the face.

@PitzKey I’m not sure why you deleted your post. It was much nicer than mine and let’s be real here. A provider that doesn’t know what they are doing is going to get someone killed because their emergency calls either didn’t connect or ended up in a regional PSAP/911 center vs the actual one. Because, once again for those in the cheap seats, telephone service is considered a PUBLIC UTILITY.


@PitzKey You gave an answer based on reality besides you seem to be angry, but this is how you learn. Don’t you. You read, watch, listen and ask questions. No matter how silly it sound. I guess that is the reason that the teachers kickout those students from their class who ask too many questions and are labeled as “difficult to handle”. There is always one man behind big giants. Think big start small. Atleast I can dream. Achieving it is a different thing. I agree with everything you said. I have my answer and now I understand. :slightly_smiling_face:

@Stewart1 Thank you. I agree. Helped me understand.

Thank you

Nope, @PitzKey wasn’t the angry one, I was.

You mean come into a community forum for a PBX and ask how to be a provider? No, it’s not unless you’re learning how to make people not take your request seriously.

You’re missing a key item in that list. Know your own limitations and abilities. If you honestly want to be a provider or anything close to it, you need to learn multiple skillsets some of them will be technical and many of them will not. Right now if you cram you’re about 6-12 months away from having a basic entry level position at a provider/carrier company. That may sound harsh or I’m stepping on your dream but it’s the reality. So if this is your dream then you need to get the basics down, get into an actual provider/carrier and learn the ropes. You have a long way to go to be close to doing anything on your own. Unless you are the money and dream guy and put that money towards a team that has all the proper skill sets.

Uhmmmm, no.



Idk, I felt it was a little rude the way it was written.

No I’m not angry, I thought you are heading in the wrong direction and wanted to make you aware of that.

No, you don’t lecture a Sangoma employee about their product, and you don’t rant about one time ads, when trying to learn how a product works.

You got this wrong.
We’re not here to discourage people from using FreePBX. We’re here to help people, get this project going etc.

But the way you posted your questions/rant/lecture it seemed to me that you have no clue anything about SIP/FreePBX, so you should first get your hands a little dirty to understand whats up with this piece of software and come back to ask questions.

Again, we encourage people to ask, report, discuss issues here, in fact this community is one of the most active telephony related forums on the internet.

Finally, yes you can succeed with providing service with FreePBX, but as Tom said, it’s not little work with easy money.

When phones are down people freak out! It depends how much clients and what hours your clients are operating but in most cases it’s a “be available 24/7” job.

Much luck with whatever you, and let us know if there’s anything else we can assist you with :slight_smile:

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You can do a pair to pair sip software, right now you can already call someone IP to IP but you can make it more intuitive like riding a plug-in for free PBX making a app for Android and iOS and people will see you in their contacts who is already on the network, you can give out PSTN like numbers, the latency will be as good as the two users internet connections, but with more and more fiber it will start working better and better, since a lot of ISPs are replacing they’re analog systems with VoIP anyways and everything is traveling on the internet you can try to do something better and try to fix the shortcomings of the current PSTN system, and maybe you’ll be the next big thing Since it’s open source and if it’s good the ATA home boxes manufacturers will start connecting to the network

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Thanks :slightly_smiling_face:

That’s encouraging and looks like an idea :slightly_smiling_face:

You’ll just have to run a server to bypass NAT fairly low cost media can go directly

Wait, did someone slip me LSD in this thread? WTH are you talking about @ITconsultant? I mean that seriously because you have now shown me the longest run-on sentence I’ve ever seen in your first reply to this thread. It absolutely makes no sense and it’s just a string of words.

Not only that, it highlights a serious (to me) problem I see on this forum (and others really). We literally have someone talking about being a service provider of voice at some level here. The same someone that has ZERO experience in Telephony, SIP, networking or any of the other ancillary skill/knowledge sets that are needed to even run FreePBX let alone any level of a voice network. The result: People encouraging it instead of discouraging it. Sorry but that’s just wrong.

So far we have one person that posted something then deleted because it was “too mean” and then we have whatever @ITconsultant said. It’s just a lofty word salad with not actual connection to anything.

This needs to be discourage. What I said was the real path that needs to be taken, plain and simple. Anything else is short cuts and delusions of grandeur. No one at this skill level should even be attempting this and those with the right skill levels and experience should be calling that. Sorry that it seems harsh but reality usually is.

This. Is. Hilarious. I mean seriously, this is just hilarious. Because, well, how?! How will this one person fix the shortcomings of the PSTN system? The system they don’t have a direct connection to? A system they have no level of ability to actual do anything with. Because unless you are one of the major top carriers that actually make up the PSTN you ain’t going to do crap with the PSTN.

Just understand that the PSTN is a collection of multiple carrier’s infrastructures and their ability to interconnect with each other. Also, not all PSTN carriers actually connect to each other. ATT might have to go through CenturyLink to get down to a Windstream CO because ATT and Windstream don’t have peering together but CenturyLink has a peer with both.

We’re just talking about Concepts, he just needs a lot of spare time and motivation, he’s not offering Anythink to customers yet, everyone starts from Level 0

Sorry I don’t see any actual concepts being discussed. What concepts am I missing?

I’m talking as a replacement in a lot of countries most people don’t even have cell phone plans to call International they use WhatsApp it’s a total replacement