Your Domain & SIP Proxy will need to be set to sip.nehos.com.au (126.96.36.199) to use this network.
The sip.nehos.com.au domain supports SIP signalling on UDP/TCP on port 5060
You will need to allow your Customer Premises Equipment (CPE) to allow use of the 188.8.131.52/26 for SIP signalling and RTP media.
For CPE equipment that uses STUN the signalling will be TCP or UDP protocol on port 5060. For sip.nehos.com.au domain IP address 184.108.40.206 & 220.127.116.11.