VOS3000 SIP default ports are 5060 and 6060
The RC4 encryption for port 5070 is defined by linknat
You can modify the mbx3000 config file to add the register port
vi /home/kunshi/mbx3000/etc/softswitch.conf
Then execute the command:
/etc/init.d/mbx3000d reload
Execute the following command to check the new port effect or not
ss -anput | grep port(you added in config file just now)