Skip to main content

TCP, TLS and Secure RTP Options - Knowledgebase / PBX, Peering, Ports and IPs - SIPcity Help Centre

TCP, TLS and Secure RTP Options

Authors list

TCP, TLS and Secure RTP Options


We support both TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) communication protocols. While UDP is by far the most common of the two protocols TCP is stated to have advantages.


TCP advantages

  • Keep Alives: SIP must periodically send out keep-alives to maintain the NAT table entry. The required frequency of keep-alives is much higher for UDP (maybe every 30 seconds) vs TCP (maybe every 15 minutes). While not relevant for small installations TCP has significant advantages within enterprise installations.

  • TLS: allows for secure encrypted transmission of SIP for deployments that require increased security by encrypting the SIP messaging between you and us. On your sid,e you should connect to tls.l2access.com.au as your proxy/host using TCP port 5061.

  • SRTP (Secure Real-Time Transport Protocol or Secure RTP): SRTP encrypts or “codes” the voice data making it impossible to decipher the conversation excep fort the person who has the decoding “key”, or the person to whom the call is being made.


Quick Guide:


Step One: TCP, TLS & Secure RTP Options

  1. Log into Account

  2. Go to the Switchboard > Select the number you wish to set up a remote call back on.

  3. Select CloudPBX > Advance > TCP, TLS & Secure RTP Options.

  4. Select one of the SIP Transport options.

  5. Enable Secure Encrypted RTP.

  6. Click Save settings to update.


Step Two: Change PBX/handset transport

  1. Log into the IP of your handset or of your PBX

  2. Select Account.

  3. Find the option to change Transport > TLS.


Helpful Unhelpful