Bug#608061: libc6: dns-lookup unusable in mixed ipv4/ipv6-networks
Package: libc6
Version: 2.11.2-7
Severity: important
Tags: ipv6
When looking up an ip-address on an ipv6-enabled system, libc tries to
find an A and an AAAA-record. But, if some machine has only an A but no
AAAA record it returns host-not-found (see tcpdump below)
So one can only connect (with e.g. iceweasel, w3m, telnet) to hosts with
both A and AAAA records (or server with cname-records)
On an ipv4-only machine this can be "solved" by disabling ipv6 completly,
but on a dualstack-machine, i found no way to fix this.
I found this on bug on two ways, an installing squeeze via d-i (the ipv4 only machine)
and via upgrading from lenny to squeeze
---------------------------- example-tcpdump ------------------------
19:47:46.941816 IP d64.w12a.fschueller.eu.57717 > ns.w12a.fschueller.eu.domain: 6813+ A? www.spiegel.de. (32)
19:47:46.942592 IP d64.w12a.fschueller.eu.47213 > ns.w12a.fschueller.eu.domain: 36087+ PTR? 254.1.168.192.in-addr.arpa. (44)
19:47:46.942768 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.57717: 6813- 1/0/0 A 195.71.11.67 (48)
19:47:46.942989 IP d64.w12a.fschueller.eu.57717 > ns.w12a.fschueller.eu.domain: 10783+ AAAA? www.spiegel.de. (32)
19:47:46.944994 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.47213: 36087*- 1/1/1 PTR ns.w12a.fschueller.eu. (109)
19:47:46.945315 IP d64.w12a.fschueller.eu.51939 > ns.w12a.fschueller.eu.domain: 54899+ PTR? 3.1.168.192.in-addr.arpa. (42)
19:47:46.946277 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.57717: 10783- 0/1/0 (85)
19:47:46.947048 IP d64.w12a.fschueller.eu.56975 > ns.w12a.fschueller.eu.domain: 6813+ A? www.spiegel.de. (32)
19:47:46.947146 IP d64.w12a.fschueller.eu.56975 > ns.w12a.fschueller.eu.domain: 10783+ AAAA? www.spiegel.de. (32)
19:47:46.948986 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.51939: 54899*- 1/1/1 PTR d64.w12a.fschueller.eu. (111)
19:47:46.949616 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.56975: 6813- 1/0/0 A 195.71.11.67 (48)
19:47:46.950718 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.56975: 10783- 0/1/0 (85)
19:47:46.951418 IP d64.w12a.fschueller.eu.40332 > ns.w12a.fschueller.eu.domain: 59564+ A? www.spiegel.de.w12a.fschueller.eu. (51)
19:47:46.951583 IP d64.w12a.fschueller.eu.40332 > ns.w12a.fschueller.eu.domain: 40272+ AAAA? www.spiegel.de.w12a.fschueller.eu. (51)
19:47:46.953307 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.40332: 59564 NXDomain*- 0/1/0 (101)
19:47:46.954779 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.40332: 40272 NXDomain*- 0/1/0 (101)
19:47:46.962379 IP d64.w12a.fschueller.eu.37847 > ns.w12a.fschueller.eu.domain: 4010+ A? www.spiegel.de. (32)
19:47:46.962585 IP d64.w12a.fschueller.eu.37847 > ns.w12a.fschueller.eu.domain: 55074+ AAAA? www.spiegel.de. (32)
19:47:46.963417 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.37847: 4010- 1/0/0 A 195.71.11.67 (48)
19:47:46.964467 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.37847: 55074- 0/1/0 (85)
19:47:46.965055 IP d64.w12a.fschueller.eu.56559 > ns.w12a.fschueller.eu.domain: 4010+ A? www.spiegel.de. (32)
19:47:46.965212 IP d64.w12a.fschueller.eu.56559 > ns.w12a.fschueller.eu.domain: 55074+ AAAA? www.spiegel.de. (32)
19:47:46.966084 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.56559: 4010- 1/0/0 A 195.71.11.67 (48)
19:47:46.967142 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.56559: 55074- 0/1/0 (85)
19:47:46.971000 IP d64.w12a.fschueller.eu.42783 > ns.w12a.fschueller.eu.domain: 59661+ A? www.spiegel.de.w12a.fschueller.eu. (51)
19:47:46.971175 IP d64.w12a.fschueller.eu.42783 > ns.w12a.fschueller.eu.domain: 40462+ AAAA? www.spiegel.de.w12a.fschueller.eu. (51)
19:47:46.972878 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.42783: 59661 NXDomain*- 0/1/0 (101)
19:47:46.974371 IP ns.w12a.fschueller.eu.domain > d64.w12a.fschueller.eu.42783: 40462 NXDomain*- 0/1/0 (101)
-- System Information:
Debian Release: squeeze/sid
APT prefers testing
APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Kernel: Linux 2.6.32-5-amd64 (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Versions of packages libc6 depends on:
ii libc-bin 2.11.2-7 Embedded GNU C Library: Binaries
ii libgcc1 1:4.4.5-8 GCC support library
libc6 recommends no packages.
Versions of packages libc6 suggests:
ii debconf [debconf-2.0] 1.5.36 Debian configuration management sy
pn glibc-doc <none> (no description available)
ii locales 2.11.2-7 Embedded GNU C Library: National L
-- debconf information:
* glibc/upgrade: true
* glibc/disable-screensaver:
glibc/restart-failed:
* glibc/restart-services: ssh openbsd-inetd exim4 cups cron
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