I have read and followed the "Reporting Problems" section on the Contact page and am providing the following details for this report based on the list of items stated there: Reverse dnsn fails on my subnet, I fear its on the sixxs's side, reverse dns works fine on my other subnet, which uses the same dns server I adminstrate. I tried removing and adding the nameserver in the webinterface, and waited for 2 days to be sure there are no caching problems. My subnet is R8014 on T18863 which connects to nlhaa01 Here is the succesfull dig on my own dns server: [18:54:19] [jeroen@HaqueBook /Users/jeroen]$ dig @servier.jeroenimo.nl -x 2001:1af8:fe04::1 ; <<>> DiG 9.4.2-P2 <<>> @servier.jeroenimo.nl -x 2001:1af8:fe04::1 ; (1 server found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 55958 ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0 ;; WARNING: recursion requested but not available ;; QUESTION SECTION: ;1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.4.0.e.f.8.f.a.1.1.0.0.2.ip6.arpa. IN PTR ;; ANSWER SECTION: 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.4.0.e.f.8.f.a.1.1.0.0.2.ip6.arpa. 604800 IN PTRhackbookpro.jeroenimo.nl. ;; AUTHORITY SECTION: 4.0.e.f.8.f.a.1.1.0.0.2.ip6.arpa. 604800 IN NSservier.jeroenimo.nl. ;; Query time: 36 msec ;; SERVER: 83.119.70.134#53(83.119.70.134) ;; WHEN: Thu Jan 1 18:54:44 2009 ;; MSG SIZE rcvd: 150 [18:54:44] [jeroen@HaqueBook /Users/jeroen]$ But when I do a query on the sixxs.net nameserver it fails : [18:54:10] [jeroen@HaqueBook /Users/jeroen]$ dig @ns1.sixxs.net -x 2001:1af8:fe04::1 ; <<>> DiG 9.4.2-P2 <<>> @ns1.sixxs.net -x 2001:1af8:fe04::1 ; (2 servers found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 44895 ;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0 ;; WARNING: recursion requested but not available ;; QUESTION SECTION: ;1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.4.0.e.f.8.f.a.1.1.0.0.2.ip6.arpa. IN PTR ;; Query time: 69 msec ;; SERVER: 2001:838:1:1:210:dcff:fe20:7c7c#53(2001:838:1:1:210:dcff:fe20:7c7c) ;; WHEN: Thu Jan 1 18:54:19 2009 ;; MSG SIZE rcvd: 90 Hop to have informed you enough..