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3CX Session Border Controller Build History

The mentioned Change Log reflects all the major changes. Some updates, additions and fixes may not be listed. 3CX is constantly improving the product and may implement fixes prior to any official release.

3CX Session Border Controller (SBC) for Raspberry Pi, Debian 9 and Windows

3CX Session Border Controller, Build 15.5.9414, February 2018

  • Obtain MAC address of local interface specified in config or first active interface (removed “eth0” hardcoded before)
  • Added ability to set maximum log size; when it’s reached, the log is renamed with .old suffix appended.
  • Fixed race condition in send function which can potentially be called from rtp and sip thread simultaneously
  • Added .sh script of SBC
  • Added commands to restart rsyslog and SBC

3CX Session Border Controller, Build 15.5.7467, December 2017

  • Removed restart at 3AM.
  • On Windows set SBC to start with a delay
  • SBC depends on network online service allowing the SBC to work only after the machine got an IP from DHCP. SBC with Static IPs will not be affected.
  • Increase the default number of RTP ports from 8 to 32.
  • Merged SBC repositories with 3CX PBX. Now in the same repository we have 3CX PBX, SBC Debian 9 and SBC Raspberry Pi.
  • If service fails it is automatically restarted.
  • Timestamps added in log.
  • Auto update SBC Linux at 3AM daily cron job.
  • By default SBC logging will log to syslog – more performant.
  • This new SBC works for Debian 9 and Raspberry PI. Debian 8 users will need to use the previous version.

3CX Session Border Controller, Build 2607, June 2017

  • SBC with TLS enabled unable to connect to server.

3CX Session Border Controller, Build 60789, January 2017

  • Support for Debian 8 x64
  • Fixed issue causing a spam of UDP traffic
  • Improved keep alive messages
  • Support 20 Extensions for Raspberry

3CX Session Border Controller, Build 60903, November 2016

  • Audio Quality improvement
  • Added multi threading feature (RP2 and RP3 models only)
  • RTP via UDP to eliminate jitter
  • Improved encryption mechanism and fixed some issues related to this
  • When public IP of SBC changes, the SBC is automatically updated
  • Fixed automatic re-connection bug
  • RTP Voice threads are given top priority (highest)

3CX Session Border Controller, Build 56341, July 2016

  • Major improvement to audio quality
  • Added multi threading feature
  • RTP via UDP to eliminate jitter
  • Improved encryption mechanism
  • When public IP of SBC changes, the SBC is automatically updated
  • Fixed automatic re-connection bug
  • Installation UI update

3CX Session Border Controller, Build 48426, February 2016

  • Added Failover option
  • Added encryption securing calls
  • Auto reconnection when network disconnects
  • Fixed one way audio caused by Hold/Resume
  • SBC now performs frequent DNS resolutions

3CX Session Border Controller, Build 44201, July 2015

  • Improved audio packet transmission removing delivery delays
  • Fixed one way audio issues
  • Added DNS SRV records for sip and tunnel to SBC
  • RTP processing from Tunnel is now set to high priority
  • RTP port allocation optimization
  • Fixed crash in Tunnel caused when Server restarts
  • Adhock conferences automatically got fixed due to issue 6.
  • Attended transfer bug between SBC and PBX phones is now fixed

3CX Session Border Controller 12.0.38923 – December 2014

  • Fixed audio delivery between two phones behind the same 3CX SBC. In some cases, audio was passing through the PBX. Now if two phones that are behind the same SBC call each other, the audio does not pass via the PBX and remains in the SBC network thus saving bandwidth.

3CX Session Border Controller 12.0.38454 – November 2014

  • Improved connection and reconnection of Session border controller to 3CX Phone System – When SBC disconnects (for any reason – network etc) and there are active calls, the calls inside the SBC are cleared. (This fixes stuck calls in the management console).

3CX Session Border Controller 12.0.35707.33 – June 2014

  • Fixed issue where connection fails and re-connection never occurred. 3CXSBC now reconnects correctly
  • Sending of data was at times congested
  • Fixed race condition leading to SBC link getting disconnected from 3CX Tunnel Service
  • Resetting of transaction ID when processing ACK from Tunnel improving SIP Packet data flow
  • Internal buffer is correctly cleared every time a re-connection occurs avoiding stale/ghost connections
  • Added checks to avoid crashes in case of packet parsing errors
  • Fixed crash on 3CX SBC raspberry when more than 15 extensions are paged
  • FQDN resolution issue addressed.
  • Fixed error 10054 related to incorrect audio delivery

3CX Session Border Controller 12.0.35530.22 – May 2014

  • Fixed memory leak causing SBC to use high memory usage.
  • Fixed exception, port already in use.
  • Fixed service stopping when FQDN cannot be resolved. Now it retries every 15 seconds.
  • Fixed issue with SBC when restarted, phones under SBC can now be Rebooted and Re-provisioned.

3CX Session Border Controller 12.0.35110.620 – March 2014


  • Extensions connected via SBC do not unregister any more.
  • Improved audio quality for phones connected behind a 3CX SBC
  • Fixed 1 way audio issue
  • Added improvements to voice calls using SRTP
  • Tunnel Password cannot contain the following characters – # or “
  • Fixed 1 way audio in Blind and attended transfers when phones behind an SBC were involved in the call
  • PNP requests are now cleared when a phone is configured via SBC

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