Using IPv6 with VNC Enterprise Edition 4.1.7 / VNC Personal Edition 4.1.2
What is IPv6? Do I need it?
If you don't know what IPv6 is then the chances are that you don't need it!
You can visit www.ipv6.org for more information on IPv6.
Platforms supporting IPv6
VNC Enterprise Edition 4.1.7 & Personal Edition 4.1.2 support both IPv6 and IPv4 on the following platforms:
- Windows XP, 2003 and above (with Microsoft TCP/IP Version 6 installed)
- GNU/Linux 2.2.x and above (with IPv6 module loaded or built-in to kernel)
On all other systems, VNC will use the IPv4 protocol only.
IPv6 support in VNC Viewer E4.1.7/P4.1.2
VNC Viewer E4.1.7 & P4.1.2 are fully IPv6-aware, and can connect to hosts specified by IPv4 address, IPv6 address or by DNS name. In the case of DNS names, VNC Viewer will attempt to connect to each address associated with the host name in turn until a connection succeeds. If a host has both IPv4 and IPv6 addresses registered with DNS then VNC Viewer will usually attempt to connect first using IPv6, and fall back to IPv4 only if that fails.
VNC Viewer uses the colon (":") as the delimiter between hostname and port number, which clashes with IPv6 addresses' use of the same character as a separator. VNC Viewer therefore allows hostnames and addresses to be escaped by enclosing them within square braces ("[" and "]"), preventing colon separators from being mis-interpreted as port number delimiters.
Handling of IPv6 addresses is dealt with by the host operating system. Compliance with the IPv6 specification is therefore dependent upon the support provided by the host operating system. In particular, functionality such as embedded IPv4 addressing (.e.g addresses such as ::ffff:192.168.0.1) is not supported on some systems.
IPv6 support in VNC Server E4.1.7/P4.1.2
VNC Server E4.1.7 & P4.1.2 are fully IPv6-aware, but is shipped with IPv6 support disabled by default, for security reasons. IPv6 can be enabled by setting "InTransports=IPv6,IPv4" (the default being IPv4 only), either on the command-line when starting vncserver under Unix, or in the registry on Windows systems.
Note that the Hosts setting available under VNC Server for Windows applies only to IPv4 connections.
At the time of writing, neither Windows' nor GNU/Linux' IPv6 implementations are fully compliant with the IPv6 specification. The only noticable side-effect of this is that VNC Server may log an error listening for IPv4 connections when running on IPv6-aware GNU/Linux systems, but in spite of this error VNC Server will in fact accept both IPv4 and IPv6 connections.