PBX configuration

Once you've set up your SIP trunk configuration, you'll need to ensure your PBX is configured to send and receive calls from Dial 9.

Firewall configuration

For calls to work correctly, you must ensure the following IP ranges are allowed through any firewalls on your network for UDP traffic:

* 2a06:5a80::/64

And in particular, that port 5060 for SIP registrations, and range 10000-20000 for voice traffic are allowed.

Incoming calls

Once you've configured your incoming call routing in Dial 9, we'll send any calls to you in the format of 01202912444@ You'll need to ensure you have the number configured as appropriate in your PBX so that you can process these calls once they are received.

Outbound calls

For outbound calls, we simply use IP-based authentication. You'll need to ensure your PBX server's IP has been added as an outbound trunk, and that you're sending your calls to Dial 9 in the correct format.

All calls must be sent to sip.dial9.co.uk.

You'll need to send a From header in E.164 format:


Where the number matches exactly that which has been configured in your Dial 9 service, and the IP is the IP address of your server. If the From header differs from this in anyway, you'll likely find your calls are rejected.

It's also strongly recommended that you set up a PAID (P-Asserted-Identity) header containing the same information, as this is necessary if the From address number is different - such as in the case of a forwarded call with an anonymous CLI.

Dialled number format

We strongly recommend that for consistency the dialled number is always sent to us in e164 format, including the international dialling code. In the case of a UK number, this will be a 44 at the start, with the normal leading 0 removed.

For example, for a UK landline you would send the dialled number as 441202912444. For a UK mobile, it would be 447777123456.

Fine-tune your preferences

There are a number of cookies we need to use in order for our website to work properly. These cannot be disabled.

However, you can disable non-essential cookies for the third-party services we use, to help us provide better customer support, measure the performance of this website and run more effective marketing campaigns.

We use Google Analytics to measure the performance of our website. We do not store any personal data and your IP address is anonymised.


We use a live chat service called Natterly so we can privide support to you where available. Various cookies are stored so chats remain active when you change page.


We use various tracking cookies to help us measure the performance of our marketing campaigns and show you content and promotions we think you’d be interested in.

Allow all
Update your preferences

Hello there!

This website uses cookies in order to provide you with the most relevant information. Please accept cookies for the best experience.

For more details see our Privacy Policy.

I’m OK with that
Cookie preferences