Friday, August 17, 2018

GNU Gatekeeper 5.0 released

I'm happy to announce the release of GNU Gatekeeper version 5.0.

This version has new features and a few bug fixes. You can download it from

Whats new ?

  • support for Azure and Alibaba Cloud in addition to AWS
  • performance optimizations, especially for multiplexed RTP and LUA
  • compatible with OpenSSL 1.1.x
  • switch to translate Facility transfers into gatekeeper TCS0 reroutes

There were also a number of bug fixes, please see changes.txt for


Thursday, April 5, 2018

GNU Gatekeeper 4.9 released

This version has new features and a few bug fixes. You can  download it from

Whats new ?

We have 2 new accounting modules: HtttpAcct and AMQPAcct that allow
you to send accounting events via HTTP GET or POST to a web service
or push them into a RabbitMQ queue.

There are also many new accounting placeholders that you can use with
any of the accounting modules and there is a new accounting event
'reject' to track calls rejected with ARJ that went unnoticed before.

The new RTP inactivity checking allows you to drop calls if there
wasn't any RTP activity for a defined amount of time.

GeoIP authentication has been significantly updated to support all
RAS and all Q.931 messages and to support the new Maxmind database
format (GeoIP2).

There were also a few bug fixes:
  • fix crash while handling RTP packets
  • fix disconnecting unregistered endpoints
  • fix crash in some Avaya endpoints when receiving GCF with a gatekeeperIdentifier
  • fix crash when using IPv6
  • fix handling of CloseLogicalChannel

Wednesday, March 21, 2018

What to do when your H.323 videoconferencing equipment reaches end-of-life ?

The big videoconferencing vendors (Polycom, Lifesize, Cisco etc.) only support their products for a limited time. After that they go „end-of-life“ and don't receive any more updates. That doesn't mean they don't work any longer. That H.323 standard how to do video conferences didn't change much in recent years, so there is no need for updates to accomodate other changes. But you there is a certain risk that they may have a security hole that doesn't get fixed any more.

Save money and stay independent

The vendors would prefer if you simply buy something new or subscribe to their proprietary “cloud service”. But to you this means spending money and a possible lock-in into their system versus just keeping systems going that run fine and owning the technology yourself with the independence that comes with it.

Move endpoints inside your firewall to private IPs

One important suggestion is to move end-of-life endpoints away from public IP addresses and to private IPs inside your firewall. Out of convenience many people used to operate their H.323 endpoints on public IPs, but nowadays its not much of a problem to use H.460 NAT traversal and move them to a safe place inside behind a GNU Gatekeeper.

If you have very old endpoints that don't support support H.460 NAT traversal, you can still do this. You just need a 2nd GNU Gatekeeper inside your firewall that tunnels the calls out to your external GNU Gatekeeper on the public IP. (Hey, its a free, you just need a 2nd server!)

Replace infrastructure devices with a GNU Gatekeeper

Some infrastructure devices (gatekeepers, gateways, proxies etc.) need to be on public IPs and thus there is a risk of exposing possible security holes to the open internet. Many of those can be replaced with a GNU Gatekeeper. Keep in mind it can be configured to do many different things that ordinary gatekeepers don't do.

Wednesday, January 17, 2018

GNU Gatekeeper 4.8 released

GNU Gatekeeper version 4.8 has been released

This version has many new features. You can download the new version from


New maintenance mode: When you need to take down your GnuGk server
(eg. for an OS update), you can switch GnuGk to maintenance mode where
it will only allow ongoing calls to finish and automatically redirects
all idle endpoints to an alternate GnuGk server.
The status port command is "MaintenanceMode <alternate IP>".

Detailed information about ongoing calls: You can now display lots of
information about each ongoing call (codecs, bandwidth used, IPs etc.).
The web interface has been extended to to show this information.

Easier installation on AWS and inside docker containers. You can now
let GnuGk automatically detect the public IP of your AWS server, even
from within a docker container. You can also automatically insert your
public/external IP into your trace file names to store logs from many
servers in the same directory.

Extended API: Call routing with external applications has been
expanded. You can now set the display names for participants and
desired reject codes on the status port. You can also access the
vendor information of all registered endpoints. The web interface has
been extended to provide this information, too.

HttpPasswordAuth has been greatly extended to fetch password
information from backend servers. We now use curl to support https
and you can add many new placeholders in your queries.

Extended screening and rewriting of display names and calling party

Important bug fixes: Multiplexed RTP is now much more robust and
password authentication to parent gatekeepers has been fixed. There
are also interop fixes for TCP keep-alives.

Please see the full change log below for more details.

Changes from 4.7 to 4.8
  • HttpPasswordAuth: support https and add new placeholders
  • PrintAllRegistrationsVerbose now also shows the endpoint vendor
  • new status port command: MaintenanceMode
  • new status port command: PrintCallInfo
  • allow placeholder %{gkip} and %{external-ip} in [LogFile] Filename=
  • fetch AWS public/elastic IP if ExternalIP=AWSPublicIP
  • new commandline switch: -e / --externalip
  • extend status port command RouteReject to set reject reason
  • extend status port commands RouteToAlias, RouteToGateway etc. to set display IE for calling and called
  • new switch: [LogFile] DeleteOnRotation=1 to delete the old logfile when rotating instead of renaming it
  • new switches: [RoutedMode] AppendToCallingPartyNumberIE= / PrependToCallingPartyNumberIE= to add any string before or after the calling party number IE when ScreenCallingPartyNumberIE=RegisteredAlias
  • when [RoutedMode] ScreenCallingPartyNumberIE= is set to RegisteredAlias, GnuGk sets calling party number IE to the registered alias (forced screening)
  • delete DisplayIE when [RoutedMode] ScreenDisplayIE=Delete
  • new switch [Endpoint] Authenicators=
  • new default: [RoutedMode] GnuGkTcpKeepAliveMethodH225=EmptyFacility
  • new default: [RoutedMode] H460KeepAliveMethodH225=EmptyFacility for Cisco interop
  • new setting "None" for keep-alive methods
  • BUGFIX(ProxyChannel.cxx) fix bugs in H.460.19 RTP multiplexing
  • BUGFIX(ProxyChannel.cxx) don't send H.460 keep-alive to non-H.460 party when calling H.460 party
  • BUGFIX(Routing.cxx) show called port in RouteRequests (as documented)
  • BUGFIX(GkClient.*) fix password authentication with parent
  • BUGFIX(Routing.cxx) remove semicolon and pipe chars from vendor string in RouteRequests
  • better handling of IPv6 GRQ without RAS address
  • BUGFIX(ProxyChannel.cxx) turn off encryption proxy if DH key is negotiated, but TCS doesn't contain any H.235 entries
  • BUGFIX(ProxyChannel.cxx) fix running in proxy mode on FreeBSD when one Home IP is set
  • BUGFIX(ProxyChannel.cxx) fix DisableSettingUDPSourceIP=1 for Windows, NetBSD, OpenBSD and Solaris
  • BUGFIX(yasocket.cxx) fix LARGE_FDSET for NetBSD, OpenBSD and Solaris