I have a similar problem after upgrade, but the consequences are less serious: lookup in the browser and similar apps is disfunctional: The consequences are serious enough though, because almost all web browsing is disabled.
Package: libc6 Version: 2.10.1-5 Severity: important Browser and other apps can no longer look up DNS names. The host program works as expected. -- System Information: Debian Release: squeeze/sid APT prefers testing APT policy: (990, 'testing') Architecture: i386 (i686) Kernel: Linux 2.6.30-2-686 (SMP w/2 CPU cores) Locale: LANG=en_GB.ISO-8859-15, LC_CTYPE=en_GB.ISO-8859-15 (charmap=ISO-8859-15) Shell: /bin/sh linked to /bin/bash Versions of packages libc6 depends on: ii libc-bin 2.10.1-5 GNU C Library: Binaries ii libgcc1 1:4.4.1-4 GCC support library Versions of packages libc6 recommends: ii libc6-i686 2.10.1-5 GNU C Library: Shared libraries [i Versions of packages libc6 suggests: ii debconf [debconf-2.0] 1.5.28 Debian configuration management sy pn glibc-doc <none> (no description available) ii locales 2.10.1-5 GNU C Library: National Language ( -- debconf information: * glibc/upgrade: true glibc/disable-screensaver: glibc/restart-failed: * glibc/restart-services: openbsd-inetd exim4 cups cron atd Simon Pepping