Before configuring your phones in FreePBX, it’s a good idea to whitelist your IP address to avoid being blocked by Fail2ban.
You need to get the Public IP by user or ask them to visit https://www.whatismyip.com/ and provide IP address.
Follow below steps to Whitelist an IP
Login to FreePBX using Putty
Run the below command to Whitelist it
iptables -A INPUT -s X.X.X.X/16 -j ACCEPT
X.X.X.X should be replacing with the IP address we got from user.
Then, run the below command to save changes
iptables-save > /etc/sysconfig/iptables
To view the IPtabes list to verify if IP has been added successfully
We can also use Asterisk console to view all extensions/registered accounts
sip show peers
Type exit to comes out from Asterisk Console