I have Fedora Core 9. The supplied "whois" client is jwhois, which does automatic redirection. Generally one can enter an IPv4 address and it will retrieve the leaf record from the best server. If I look up a Google address 2001:4860:b006::69 it retrieves a Google record from ARIN. Sometimes it returns 2 netblocks e.g. for 66.199.142.234 and I can manually retrieve the relevant one by e.g. "whois NET-66-199-142-224-1" which looks in ARIN If I enter my tunnel address, I get 2 netblocks NET6-2001-4978-1, NET6-2001-4978-F-1. If I try "whois NET6-2001-4978-F-1" it looks in Internic and fails. If I try "whois NET6-2001-4978-F-1@whois.arin.net" it gets a SixXS record, but does not redirect to sixxs. If I try "whois NET6-2001-4978-F-1@whois.sixxs.net", it finds nothing. If I try "whois 2001:4978....::2@whois.sixxs.net", I see my full tunnel record This probably represents an issue with jwhois rather than a SixXS problem. But the end user result is "whois of tunnel addresses doesn't work" jwhois-4.0-8.fc9.x86_64 updated with latest jwhois.conf from http://cvs.savannah.gnu.org/viewvc/jwhois/jwhois/example/jwhois.conf I have not yet tried to understand jwhois or its config file