SfB Online: Number porting in the UK


Step by step process

  1. Download and complete the Letter of Authorization (LoA) from the Microsoft site (see link above).
    Note: The “To” Carrier refers to your existing service provider or carrier.
  2. Submit porting form to ptneu@microsoft.com.
  3. You’ll receive a reply back in a few hours with your Port Order ID along with any questions.
  4. Porting is accepted by Microsoft and submitted to the Losing Carrier.
  5. Losing Carrier has 3 days to reject the request or issue a Firm Order Commitment (FOC) notice.
    If accepted, the porting date is confirmed.
    If rejected, engage in back and forth with Microsoft and Losing Carrier to get the information on the form correct.
  6. One day after the FOC notice is received, the numbers will be available in the SfB Online Portal. They will have a status of “Transfer pending”. They can be allocated to users but inbound calling won’t work until the porting is complete. SfBPortal-Pendingtransfer
  7. Three days before the port is scheduled is the last chance to cancel the port.
  8. On the porting day, at some point after the porting time, calls will start being directed to SfB users.
  9. Once the port is confirmed, Microsoft will convert any user numbers to Service numbers.
  10. Crack open a <beverage> and celebrate a job well done.

User experience during the porting window

During the porting window, there should be no disruption to calls.

Outbound calling from SfB will continue to work. Once the port is complete, CLI should automatically update to the new DDI number.

For inbound calling, at some point during the porting window calls will stop ringing on the old handset and start ringing on the SfB client.

Calls that are already established will continue until one party hangs up.

Porting timeline

Based on my experience, the timeline for porting to Microsoft is very similar to other telecoms companies. And will look like the diagram below:


The process is also governed and regulated by OFCOM in the UK, so telcos are legally required to comply with valid requests.

Gotchas and lessoned learnt

  • The form doesn’t ask for it but you will need to provide either the Organisation ID or *.onmicrosoft.com domain.
  • The initial response from the porting team was good, we had the Port Order ID within 30 minutes of emailing in.
  • All numbers are ported in as user number and you can then convert select numbers to service numbers.
  • Pick a migration date at least 20 working days in the future.
  • 3 days notice to cancel a request.
  • Numbers are available in the SfB Online portal once the losing carrier has accepted the request. They have a status of “Transfer Approved”. You can assign them to users at this point, however, inbound calling won’t work till the agreed port day.
  • Converting from a User number to a Service number takes 20 minutes, can only be done once the port is complete and does involve the number being out of service while being converted.

Finding your onmicrosoft.com domain

Admin Console

The organization ID can be found from the Azure Active Directory Admin Center -> Azure Active Directory -> Custom domain names.

From the list search of the <>.onmicrosoft.com entry.



Once you are connected to Azure ID run Get-MsolDomain and look for the <domain>.onmicrosoft.com entry


Finding your Organisation ID

Third Party Website

Some kind folks have built a website that will find your Org ID for you: Link Simply enter your office 365 domain and it will display the Org ID. The site uses OpenID Connect which is an identity layer that sits on top of OAuth 2.0.

Admin console

The organization ID can be found from the Azure Active Directory Admin Center -> Azure Active Directory -> Properties  -> Directory ID.

It looks like a GUID type string. EG. a3gbd34b-14bd-5304-c380-774f60aa533b


Home Lab – Part 1: Goals and design

As with any project, it’s always a good idea to set out the purpose and objectives.


To provide an environment I can use to explore Skype for Business and the supporting technologies(SBCs, IP Phones, SQL, Exchange,  etc). Also as an environment I can use to test specific scenarios and replicate customer environments and issues.


  • Build a two host VMware environment with vCentre for management.
  • Build a multi-VLAN network based on Cisco switches and routers.
  • Build a LackRack
  • Build Windows environment (ADDS, DNS, DHCP, PKI, SQL, Exchange etc.).
  • Install and configure SfB.
  • Install and configure PfSense Firewall, Kemp HLB, AudioCodes SBC and AudioCodes MP114 (analogue gateway).


Rack, power and cabling

After some searching I came across LackRack. Looks like an interesting (and cheap) solution. I’ll be using the Lack Coffee table for the extra length.


My “secure data centre location” aka the garage already has power, so that’s nice and easy.

Cabling – I need to get a physical network cable run between the study (1st floor) and garage (directly below). Erm.. drill a hole in the ceiling? I’ll consult with a sparky about this to avoid property damage…


Pretty basic network, using a pair Cisco C3750 and a 1841 Router. Currently planning to include 4 virtual networks:

  • Server VLAN – Virtual servers and appliances.
  • Client VLAN – Physical clients and IP phones.
  • Internal DMZ VLAN- SfB Edge int interfaces and reverse proxy.
  • External DMZ VLAN – SfB Edge ext interfaces, “outside” clients and reverse proxy.

I also plan to add a firewall (probably a PfSense) once the VMware environment is up and running.Lab-Diagrams-Network-v1

This should allow me to test most scenarios and also gives me an excuse to finally learn Cisco networking.


The VMware layer will be based on two Dell R710 (2x X5650 2.66GHz 96GB) from eBay. They should be ESXi ready. So hopefully the install will be straight forward. Once the hosts are built, I plan to install vCenter as the first virtual machine.

The VM data store will be hosted on my existing Synlogy DS1515+. Planning to try out iSCSI as the access protocol.

All the other bits

Once I have the network and VMware environments installed and working, I’ll do a seperate post detailing the design of ADDS, DNS, DHCP, Exchange, SfB and all the other things I want to test.

So there we go, part 1 of my plan for my home lab!