SixXS is a IPv6 tunnel provider known to cut IPv6 connections for reasons such as hosting sites with politically correct information, critism of their policy or just no reason at all.
 "Nice organization"
SixXS organization is really only:
- Jeroen Massar (Works for IBM Zurich Research Laboratory)
- Pim van Pelt (Works for Google)
Jeroen Massar is sometimes described as "an arrogant little man" who goes "sniffing around looking for reasons to kick people off their service". This view seems to be shared by many ex-SixXS users. Other people have described their experience with SixXS two admins as:
"I used to have a tunnel provisioned from SixXS but they disabled my account over an email asking for a response to a question. Nice organization they have there."
Tyler, on the OCCAID mailing list
It's interesting to note that Jeroen Massar, who seems to spend quite a lot of time browsing the internet for IPv6-related websites, had this to say about this particular page when he noticed it:
"In case somebody does have constructive arguments, please raise them at firstname.lastname@example.org we are very open to valid discussions."
This statement is interesting, specially because numerous people have reported that mailing sixxs with constructive arguments is enough to get a tunnel closed.
It must also be mentioned that Jeroen Massar frequently refuses to state why he closes random tunnels and insists that user-accounts he's blocked for no reason stay blocked for many years.
 Using IRC is "abuse"
SixXS, with a "NAZIS like level of policy", closely monitors their users and close accounts for things like having "9 IRC Connections" from their tunnel. The most disturbing element to this particular story, however, is not that SixXS closes the accounts for having a few connections to IRC servers. What is really alarming is that SixXS monitors the usage of IPv6 tunnels closely and keep track of how many open connections there are and where they are going.
SixXS FAQ on "Internet Relay Chat" claims that "When users use IRC to chat (and not to evade policy or run bots) and don't cause trouble, it is permitted to chat via SixXS tunnelbrokers.". However, Jeroen Massar - when trying to explain away the information on this page - admits that SixXS views just using IRC as "abuse". Keep this in mind if you consider getting a IPv6 tunnel through SixXS: Just using IRC may get your account closed even though their so-called "FAQ" claims you can.
It must be mentioned that SixXS are not only known to close people's tunnels for hosting "politically incorrect" sites and services, they are also known to null-route IPv6 services for no reason - specially sites who write anything even remotely critical about SixXS.
 Frequency of rejected tunnels
About half the new requests for tunnels through POPs who use SixXS to give tunnels to end-users are rejected according to their own graphs at https://noc.sixxs.net/misc/requests/
Tunnels who are later closed because SixXS staff find that are used to host websites they don't like for some reason or simply because some of the rude SixXS personell thinks they should place Internet police and close the tunnel are not in the graph. If what is written about SixXS on other sites on the Internet is close to correct then we can assume about half of the initially approved tunnels are eventually closed; thus: about 1/4 of tunnels requested at SixXS are permanently approved (approved and not closed because of any random reason within a year).
 Boycott of SixXS
I received a link to this article after I recently (03Jun09) posted the following on the OpenNIC m/l [header edited to better reflect original intent of post]:
REQUEST FOR ALL OPENNIC MEMBERS AND OTHER ALTERNATE ROOT ADVOCATES TO BOYCOTT SIXXS
As an OpenNIC member, I am requesting that we take a stand against self-appointed "internet guardians" who believe that OpenNIC and other alternate roots are poison to the continued well-being of the Domain Name System. Specifically, I am asking each of you to (1) immediately move any IPv6 subnets you may have with SixXS to Hurricane Electric or another 6-to-4 tunnel broker; and (2) send an email to Jeroen Massar, maintainer of SixXS, expressing your outrage over his self-appointed role as an "internet guardian." If you do not currently have a 6-to-4 tunnel with SixXS, I urge each of you to e-mail Jeroen anyway and express your displeasure with his actions and attitude towards alternate roots.
By way of background: On or about May 24, my 6-to-4 tunnel was "administratively set down" by SixXS, and my access to the SixXS forums and tracker engine was revoked. Despite numerous requests for clarification, Jeroen and SixXS have refused to acknowledge the reasons why my 6-to-4 tunnel was disabled. However, log entries in my account indicate the following actions were taken against me shortly after I posted a forum message in the SixXS "General" forum announcing Aaron Angel's new OpenNIC Tier 2 server availability on IPv6:
T19893 violates RFC2826
Tunnel to 22.214.171.124 was admin disabled
SixXS fully supports RFC2826, thus please don't abuse our forums as a mechanism outing in contrast to that
Set AllowForum to N
Posted a message to the forum
Posted a message to the forum
Apparently, my access was removed, and my subnet was disabled, within 30 minutes of posting. This was posted in a forum that has numerous other posts announcing various DNS services available via IPv6. No explanation was ever given me as to why my subnet was disabled (and despite the fact that my subnet was *not* hosting the Tier 2 in question), and I received no warning that my access would be terminated.
The reference to RFC2826 ("IAB Technical Comment on the Unique DNS Root" [informational]) is one that is often made by critics of the alternate root system, but one that is ultimately non-applicable to OpenNIC: RFC2826 specifically discusses the dangers of "colliding TLDs," and the OpenNIC charter and policies specifically exclude establishing new TLDs that collide with existing ICANN TLDs.
It is apparent to me that Jeroen has taken it upon himself to enforce his brand of compliance on his small segment of the Internet. Compare this to Hurricane Electric, another 6-to-4 tunnel provider that specifically encourages us to provide our services to the Internet community:
Nothing we have in place currently would prevent you from doing such a thing. Do be aware that it is a free service, and it's provided on a best-effort basis, especially as tunnels can be prone to odd hiccups. If that's all fine with you, then go ahead.
We should not have to stand for this level of contempt, and I again urge each of you to let Jeroen know that you will not permit him to serve as your Internet gatekeeper.
 https://www.sixxs.net  http://www.tunnelbroker.net  email@example.com (He seems to prefer digitally-signed emails)  firstname.lastname@example.org  http://www.ietf.org/rfc/rfc2826.txt  http://wiki.opennic.glue/OpenNICCharterAnnotated  Personal communications, 29 May 2009
 In bullet summary
See Free IPv4 to IPv6 Tunnel Brokers for good & stable IPv6 tunnel brokers who don't close random tunnels for no reason. Only use SixXS if you don't really need IPv6 and don't mind that some sites are nullrouted for no reason and that your connection may suddenly be closed for no reason.