# Use SIP2SIP to receive unlimited incoming calls


Here's a simple tutorial on how you can use the Zoiper app and sip2sip to receive unlimited incoming calls on your FlyNumber (ie. Virtual phone number)

This **does not require** the use of our cloud PBX system.

Quick mention: If you haven't noticed we've updated our PBX-phone system. It's a powerful system and currently priced at $13 a month (We suggest you [check it out](https://www.flynumber.com/products/phone-system) and lock in price as it will be going up soon)

First you'll need an account from sip2sip, it's free and [simple to sign up](https://mdns.sipthor.net/register_sip_account.phtml). I've used them for years and never had an issue. (Check your spam/junk folder for their emails). 

You can set multiple numbers to the same SIP2SIP account. 

For example, you can have a [number in London](https://www.flynumber.com/cities/united_kingdom/england/london/) and a [phone number in Sydney](https://www.flynumber.com/cities/australia/sydney/) ring to the same Zoiper account

Take your account username and password ( the ones from sip2sip.info) and enter them into a SIP client , a free one for iOS and Android is Zoiper ( we really like "Groundwire" , one-time paid app but worth it)

Choose "Yes" to "Do you have a username and password", and then "manual configuration"

You'll only need the user, password and domain (which is sip2sip.info)

![Add SIP account options with fields for domain username and password](/blog/images/IMG-4663-569x1024.jpg)

### **Important:**

Under "Network settings" for the account you just created, **change Transports to TCP and disable STUN** as you see below

![Network setting options screen for transports and STUN](/blog/images/IMG-4664-581x1024.jpg)

### Final Step

You'll need to set the forwarding on the FlyNumber side to a VOIP provider

On FlyNumber ( Under "[My FlyNumbers](https://www.flynumber.com/orders)")   
  
Change the forwarding to "VoIP" , screenshot below

Protocol is SIP

Host is sip2sip.info

"details" is testingforfly (in our case)

![Screenshot of the FlyNumber change forwarding panel ](/blog/images/Screen-Shot-2021-05-02-at-11.36.59-PM.png)

All set, calls from your local FlyNumber will now ring to your app. 

There are a bunch of [settings on sip2sip](http://x.sip2sip.info) you can check out as well ( voicemail etc.)