Article · Wikipedia archive · Last revised Jul 11, 2026

AICCU

AICCU was a popular cross-platform utility for automatically configuring an IPv6 tunnel. It is free software available under a BSD license. The utility was originally provided for the SixXS Tunnel Broker but it can also be used by a variety of other tunnel brokers.

Last revised
Jul 11, 2026
Read time
≈ 3 min
Length
586 w
Citations
13
Source
AICCU
Original authorJeroen Massar
ReleaseAugust 1, 2004 (2004-08-01)1
Stable release2012-02-02 (February 2, 2012 (2012-02-02)) [±]
Preview releaseNon [±]
Written inC
Operating systemCross-platform
Available inEnglish
TypeInternet
License3-clause BSD
Websitewww.sixxs.net/tools/aiccu/

AICCU (Automatic IPv6 Connectivity Client Utility) was a popular2 cross-platform utility for automatically configuring an IPv6 tunnel. It is free software available under a BSD license. The utility was originally provided for the SixXS Tunnel Broker but it can also be used by a variety of other tunnel brokers.

History and development

AICCU was written and maintained by Jeroen Massar. Various patches from other persons have been incorporated, these persons are acknowledged in the field3 for their contributions. AICCU is the successor of the Windows-only and Linux/BSD-variety of the Heartbeat tool that was provided by SixXS, solely to use the Heartbeat protocol. When the AYIYA protocol came into existence it was decided that to support this new protocol it would be better to merge the Windows and Unix trees into one program and give it a better appearance. The name of the Heartbeat tool was then changed to reflect that it did more than providing mere support for the heartbeats.

Award of excellence

AICCU has won the Award of Excellence in the Implementation Category of the 2004 Edition of the IPv6 Application Contest.4

Supported protocols

The following tunneling protocols are currently supported:

  • 6in4 - Standard IPv6 in IPv4 tunnels using protocol 41 in the IPv4 protocol header.
  • AYIYA - For IPv6 over IPv4 UDP in a secure manner and being able to work through a NAT.
  • 6in4 Heartbeat - used for dynamic 6in4 tunnels

AICCU primarily uses the TIC protocol to retrieve the configuration parameters of the tunnel automatically that the user wants to have configured.

Support for other tunnel brokers

AICCU finds available tunnel brokers by looking up the TXT DNS records from "_aiccu.sixxs.net".5 The latter allowed a local network to add their own tunnel broker(s) by adding records in the domains configured in their search path. Non-local tunnel brokers could then be added by requesting the SixXS staff to add an entry to the global DNS records.

Supported platforms

The following operating systems/platforms/distributions are supported by AICCU:

Various distributions have an AICCU package included in their distribution.6789101112

Usage

The main usage of AICCU was in combination with the SixXS tunnel broker service.

There are other ISPs who have implemented parts of the protocols that AICCU support, for instance the Czech ISP NetBox uses AICCU to configure tunnels automatically for their users 13 by providing a TIC (Tunnel Information and Control protocol) implementation that ignores the username/password/tunnel_id but uses the source address where the TIC connection originates from to determine and return the tunnel configuration using the TIC protocol, which AICCU then uses to configure the tunnel.

See also

See also

Free software portal

References

References

External links