Usage Example: TLS Tunnel

Suppose you have 2 locations and want to connect them securely over the public internet.

GnuGk can encrypt call signalling between those locations using TLS and encrypt the media (RTP) using H.235.6 (AES encryption).


Click to enlarge

Example Configuration

See the manual section on TLS for more details and examples how to generate the OpenSSL certificates.

GNU Gatekeeper 1 (location prefix 01) GNU Gatekeeper 2 (location prefix 02)
[Gatekeeper::Main]

[RoutedMode]
GKRouted=1
H245Routed=1
CallSignalPort=1720
AcceptUnregisteredCalls=1
; make sure H.245 gets tunneled for TLS
H245TunnelingTranslation=1
; add AES media encryption if the endpoint doesn't encrypt itself
EnableH235HalfCallMedia=1
; only allow encrypted calls
RequireH235HalfCallMedia=1
; change the media key after 2^31 operations
EnableH235HalfCallMediaKeyUpdates=1

[Proxy]
Enable=1

[ModeSelection]
0.0.0.0/0=PROXY
; only use routed mode for local calls
192.168.0.0/18=H245ROUTED

[TLS]
EnableTLS=1
PrivateKey=/path/to/server.pem
Certificates=/path/to/server.pem
CAFile=/path/to/rootcert.pem
Passphrase=MySecret
CheckCertificateIP=1

[Gatekeeper::Auth]
FileIPAuth=required;Setup

[FileIPAuth]
; allow all calls from local network
192.168.1.0/24=allow
; only allow TLS encrypted and authenticated calls from elsewhere
any=onlyTLS

[RasSrv::PermanentEndpoints]
; the GnuGk in the other location, serving prefix 02
1.2.3.4:1300=remote-gw;02

[EP::remote-gw]
; use TLS to call remote GnuGk
UseTLS=1
 
[Gatekeeper::Main]

[RoutedMode]
GKRouted=1
H245Routed=1
CallSignalPort=1720
AcceptUnregisteredCalls=1
; make sure H.245 gets tunneled for TLS
H245TunnelingTranslation=1
; add AES media encryption if the endpoint doesn't encrypt itself
EnableH235HalfCallMedia=1
; only allow encrypted calls
RequireH235HalfCallMedia=1
; change the media key after 2^31 operations
EnableH235HalfCallMediaKeyUpdates=1

[Proxy]
Enable=1

[ModeSelection]
0.0.0.0/0=PROXY
; only use routed mode for local calls
192.168.0.0/18=H245ROUTED

[TLS]
EnableTLS=1
PrivateKey=/path/to/server.pem
Certificates=/path/to/server.pem
CAFile=/path/to/rootcert.pem
Passphrase=MySecret
CheckCertificateIP=1

[Gatekeeper::Auth]
FileIPAuth=required;Setup

[FileIPAuth]
; allow all calls from local network
192.168.1.0/24=allow
; only allow TLS encrypted and authenticated calls from elsewhere
any=onlyTLS

[RasSrv::PermanentEndpoints]
; the GnuGk in the other location, serving prefix 01
1.2.3.5:1300=remote-gw;01

[EP::remote-gw]
; use TLS to call remote GnuGk
UseTLS=1

You could also configure the remote GNU Gatekeeper as a neighbor, but beware that the RAS traffic between neighbors will show meta data (whois is caling who) in clear text!




Last updated: 30. Oct 2016
Page maintained by Jan Willamowius