The IP addresses you will receive calls from depend on the preferred server you chose in the mapping you created for the DID number.
E.g. if you chose USA as preferred server, the call will be sent from USA range of addresses:
46.19.209.10
46.19.209.11
46.19.209.12
46.19.209.13
46.19.209.14
46.19.209.15
46.19.209.75
46.19.209.76
46.19.209.77
46.19.209.78
46.19.209.79
46.19.209.80
In addition, RTP media may arrive from 46.19.209.0/25, please allow the range in your firewall.

Will I Receive Calls From Any Of Your IP Addresses?