ENUM - outgoing and incoming

[RichardCrabb1]

I have been experimenting with direct SIP, with the aim of implementing ENUM both outbound and inbound. I have figured out how to make inbound ENUM calls. The DNS allows with ENUM a lookup between a phone number, via e164.arp, and direct sip such as [email protected].

Outbound calls using ENUM seem not to be possible? Is there an answer to this? I know that FreePBX allows an ENUM outbound trunk. There is no such thing with 3CX, or so it would seem.

ENUM looks very attractive as it can make phone calls very low cost - as long as customers and suppliers (or whoever) all participate in ENUM. Also, ENUM is now officially available in the UK.

Kind regards
Richard Crabb

 

[nwhitfield]

Don't forget that you'll need good passwords (and the anti-hacking options in v9) if you're allowing direct SIP.

I was going to tinker with this sort of thing, but allowing incoming SIP from anywhere also lets script kiddies try their luck at breaking into your PBX too.

 

[RichardCrabb1]

Yes you are absolutely right. I wonder how robust 3CX is to provide this kind of direct SIP? So far (touch wood) I have not noticed any attempts at hacking. I am running version 9 with SP2 (the security update).

 

[paul.hadley]

Yes you can get ENUM working 3CX by using Sipbroker.

Sipbroker will check any number against 5 data bases :-

e164.arpa.
e164.org.
e164.info.
enum.org.

In order to make this work you need to place the call against sipbroker.com in the following format (I am in the UK but I am sure you can adapt this to any country)

Original Number 0121 123 4567 (UK)

Call placed to [email protected]

This will either return the direct sip address, ie [email protected] or 441211234567 to try on another line.

To achieve this first set up a PSTN device (I used a spa3012 template) with the address of the unit as sipbroker.com rather the local address of the spa as you usually would and the port 5060.

After setting up a device change its properties so that "Require registration for:" is set to "Do not require"

Now set up a dial rule, in our case we don't use a (9) for an outside line, the leading zero (0) sends the call to our Voip Provider.

So set a rule that all calls starting with a (0) are dialed onto the PSTN device you set up with one digit stripped (0) and prepend with (44) so that 0121 123 4567 becomes 441211234567, the format sip broker requires.

This will cause a look up at sipbroker and if a direct sip address is returned the call is placed to that sip address toll free.

There are then two ways to deal with the call if no sip address is available and the number in international format is returned.

Either set up a separate dial plan so that all calls starting with (44) are sent to your usual Voip provider or ensure there is no call plan for such numbers and then in your original dial plan make your normal service provider the second route, either will work fine.

Please remember to go to "Settings" - "Advanced" and allow calls to direct Sip Url's

The result of this should be all external UK calls (0) are placed against sip broker for look up, dialed directly if a sip address is available or returned to be dialed through your normal provider. The procedure seems to take less than a second so is transparent to the user.

And of course, if you have a number you want to link to a sip address you can register it quite easily with e164.org.

 

[RichardCrabb1]

Paul,
That is very useful - thank you. I have setup a voip provider - generic trunk rather than setup a gateway and it all works fine, for inbound and outbound calls. I have registered a few numbers with e164,org and they work OK as well.

Thanks again
Richard