Bug#777149: libapr1: apr_sockaddr_info_get() fails when eth0 has IPv6 only (can't determine the FQDN), e.g. with DHCP at boot

[Vincent Lefevre <vincent@vinc17.net>]

Package: libapr1
Version: 1.5.1-3
Severity: normal

After the latest reboot, I have the following errors in /var/log/boot
for apache2:

  AH00557: apache2: apr_sockaddr_info_get() failed for ypig
  AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1. Set the 'ServerName' directive globally to suppress this message

This error didn't reappar after "service apache2 restart".

My /etc/hostname file contains:

ypig

my /etc/hosts file contains:

127.0.0.1       localhost
127.0.1.1       ypig.lip.ens-lyon.fr    ypig

# The following lines are desirable for IPv6 capable hosts
::1     localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

and my /etc/nsswitch.conf contains about the "hosts" line:

hosts:          files mdns4_minimal [NOTFOUND=return] dns mdns4

so that there should be no problems to determine the FQDN, even if the
non-local network is not completely working yet.

This bug is similar to:

  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=629899

And I confirm that this comes from the same problem, i.e. when eth0
has IPv6 only, as shown below:

# ip address del 140.77.13.48/23 dev eth0
# service apache2 restart
[....] Restarting web server: apache2AH00557: apache2: apr_sockaddr_info_get() failed for ypig
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1. Set the 'ServerName' directive globally to suppress this message
. ok 
# ip address add 140.77.13.48/23 dev eth0
# service apache2 restart
[ ok ] Restarting web server: apache2.

-- System Information:
Debian Release: 8.0
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.16.0-4-amd64 (SMP w/8 CPU cores)
Locale: LANG=POSIX, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)

Versions of packages libapr1 depends on:
ii  libc6              2.19-14
ii  libuuid1           2.25.2-5
ii  multiarch-support  2.19-14

libapr1 recommends no packages.

libapr1 suggests no packages.

-- no debconf information