Author Topic: I need CNET Numbers!  (Read 1167 times)


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Re: I need CNET Numbers!
« Reply #15 on: September 11, 2018, 08:56:19 AM »
I really donít understand how it all works...or at least what all the options are. If You host the 937 NNX woukd I only be able to get individual 7 digit numbers? What would I need to have to get say the 937-8000 or 8800 Group incoming to a 5th selector or connector in a SxS demo switch?


I really wish I knew how to work with Step by Step switches. Can't help you there although if you can call me we could have a long chat on how all that stuff works because that stuff is way above my head.

C*NET 1-229-0001

Offline AE_Collector

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Re: I need CNET Numbers!
« Reply #16 on: September 12, 2018, 11:58:00 AM »
It would require that if 1 937-8xxx were dialed, the connection would then come to my system where if I connected into the input of say the 5th selector, the final 3 digits would be sent dial pulse to the 5th selector which would advance in my SxS system to the Connector switch for the last two digits.

It would be a matter telling your end what numbers dialed should route to me and then what digits to send (resend). I would assume this programming would be quite flexible allowing for routing to be determined down to the last digit or two but then as many digits as necessary being sent, even all 7 digits so that I could connect into my first selector and have the call proceed through 1st through 5th selectors and to the connector.

Iím not certain what would hold up my C (Sleeve) lead on an incoming call though, I bet I need an Incoming Selector or maybe an Incoming Trunk in my switch train to perform this function. I havenít worked on SxS for decades now so most of the little bit that I used to know is gone now! In any event, all that is needed from the host is the ability to create a trunk group that knows when to route to me or anyone else based on what has been dialled and what digits to send.


Offline andy1702

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Re: I need CNET Numbers!
« Reply #17 on: June 09, 2019, 06:09:41 AM »
Going back a few posts in this thread... As far as I'm aware there is no mechanism within C*net that checks numbers against IP addresses. Anyone can set up a C*net server without any kind of number allocation provided they don't want to receive incoming calls. The numbers are only allocatted on a central server (called the e-num server) which is where each server calls up to ask what physical IP address a given number should be connected to. HOWEVER, the directory of numbers and physical addresses can be kept on your own C*net server, so there is no need to reference the e-num at all. This is especially handy of the e-num server goes down for any reason. My own server, which is a HP thin client running Astlinux, has a long list of numbers and physical IP addresses it uses for connection. Only if it doesn't find the dialled number in that list does it then go and ask the e-num. So 99% of the time my C*net calls don't go via the e-num server at all.

The only problem with storing the directory locally is that you have to keep it up to date.

The problem of losing access to C*net when you change your IP address is to do with how the internet and particularly routers work with ATA boxes. Most people these days have dynamic IP addresses. This means whenever they turn their router off and on again it coimes back up with a new IP address assigned by your ISP. This IP address is your 'external IP address', which is your address out on the internet.

Think of it like this... Your router is the front door of your house and your ATA box is inside your house. Your external IP address is a number nailed to the outside of your front door. You can't actually see the number from inside. The asterisk hosting your ATA delivers your calls by looking up and down your street to find your number, then posting calls to you through your door. However if you have a dynamic IP, the number on your door may have been changed by your ISP, which means the asterisk can't find you. For this reason your ATA periodically calls the asterisk to say "I'm here at number 20". However your ATA can't see the outside of the door, so doesn't know if the number has been changed. This is where something called a STUN server comes in. A stun server walks up and down your street listening for ATAs and other devices shouting from behind doors. Your ATA says something like "excuse me, I'm locked in. Can you tell me what the number is on the outside of my door please?" Then the Stun server looks at the outside of the door and shouts back to the ATA "You're at number 32". Your ATA can now call up the hosting asterisk and say "next time you have a call for me please bring it to number 32, not number 20".

Most ATAs have a setting to call up a STUN server for help. You just put in the STUN server details and your ATA will do the rest. If you don't set up a link to a STUN server then when your IP address changes the Asterisk won't be able to connect with your ATA and you'll lose the connection.

Now if you're running your own asterisk server on C*net or other systems then the ATA's will always need to know where your asterisk is so they can send the periodic message to say where they are. If your Asterisk has a dynamic external IP address, then using something like will solve that problem. Any ATAs connecting in from across the internet just go to and no-ip forward the message onto the asterisk because no-ip always knows the current address.

So to sum it up...
If your have a dynamic external IP address and you have an ATA that's hosted by someone else remotely, you need to set up a STUN server in the ATA settings.
If you have your own asterisk box on C*net then you need to register with a service like to get a static address to tell anyone with an ATA wanting to connect to you.

I hope that's cleared some of the mysteries up of how C*net works.

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