Red Hat Bugzilla – Bug 57870
IPv6 reverse IP queries incorrectly formatted
Last modified: 2016-11-24 10:13:51 EST
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Description of problem:
With glibc 2.2.2, IPv6 reverse queries are formatted correctly, according
With glibc 2.2.4, IPv6 reverse queries are formatted differently:
which meets neither RFC1886 nor RFC2874. RFC1886 mandates the use of the
nibble based .ip6.int. domain, where as RFC2874 mandates the use of
\[xprefix/length].ip6.arpa. bitstring queries.
Therefore, glibc 2.2.4-based systems are unable to perform any IPv6 reverse
Note also that RFC2874 recommends that the old RFC1886 method is tried in
addition - this seems to be a sensible idea since the .ip6.arpa domain
appears to be currently empty.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. setup two ipv6 hosts with RFC1886 and RFC2874-compliant nameserver PTR
2. login over ssh from one host to the other host.
4. host <ipv6 address>
Actual Results: netstat returns only numeric addresses
host returns a valid name record.
Expected Results: netstat should display the name.
bind 9.1.0-10 used.
glibc 2.2.2 works correctly, sending RFC1886 compliant PTR requests.
Only ip6.int nibble-based structure was moved under ip6.arpa. Conversion
to bitstring labels was not intended by the BCP document. This has been
by the author of the draft.