If you use Asterisk, then the configuration required on your server is quite straightforward.
In the relevant part of your Asterisk "iax.conf"
insert the following lines:
[Username]
type=user
username=Username
secret=Password
context=freevirtualnumbers-in
host=dynamic
Additionally, in your "extensions.conf", insert these lines:
[freevirtualnumbers-in]
exten => Telephone_number,1,Dial(SIP/201)
Please note that Telephone_number is the user portion of the destination you configured (IAX2/Username:Password@Ip_address/Telephone_number), and you should replace the Dial(SIP/201) part with an Asterisk function to route the call to your phone or a number of phones. This example assumes your phone is logged into your Asterisk server as extension "201".
If you have purchased a block of numbers, repeat the above for each number.
Finally, please note that the IAX Forwarder packages allows INBOUND calls only.
For an easy and cost effective way to make outbound calls from your Asterisk server, you might be interested in our IAX Calling package
Example:
You have purchased 0870 100 100.
Given the Username: Test1 and the password: freevirtualnumbers
You will have set up your Destination as:
IAX2/ Test1:freevirtualnumbers@81.187.77.256/44870100100
Notice the destination has been converted into international dialing standard
In the relevant part of your Asterisk "iax.conf"
insert the following lines:
[Test1]
type=user
username=Test1
secret=freevirtualnumbers
context=freevirtualnumbers-in
host=dynamic
In your "extensions.conf", insert these lines:
[freevirtualnumbers-in]
exten => 44870100100,1,Dial(SIP/201)