Issuing "wget http://distfiles.gentoo.org/" sometimes timeouts resolving the hostname, sometimes works immediately. But I can't reproduce the issue with executing "strace wget http://distfiles.gentoo.org/". In both cases using tcpdump, I can see at least one DNS answer to the query. I have two DNS servers in resolv.conf, the first one with an IPv6 address, and the second one with IPv4 address. wget uses the first one both on resolution success, and failure. On success, it can get files from distfiles.gentoo.org over IPv6. Timings: On failure I can see this in tcpdump: .926933 s: request for A record .927030 s: request for AAAA record (less than 0.0001 sec later) .927410 s: answer for AAAA record (no response for the request of A record) wget is asking for DNS names "too rapidly"? (hence the almost impossibility to reproduce it with strace's slowdown?) Reproducible: Sometimes Steps to Reproduce: execute "wget http://distfiles.gentoo.org/" Actual Results: Sometimes it gets stuck with the dns resolution. Expected Results: Always resolve when the DNS server answers. There is no physical network between the DNS server and system running the wget command. The (caching) DNS server is on a XEN dom0 with netback (with a bridge), and wget running on XEN domU (paravirtual), with netfront. resolv.conf on the domU has three lines in it: a search line with 3 local domains an ipv6 address with the dom0 nameserver an ipv4 address with the dom0 nameserver wget version: 1.12-r3 USE="+idn +ipv6 +nls +ssl -debug -ntlm -static" bind version (on dom0): 9.7.3_p1 USE="+berkdb +doc +idn +ipv6 +ssl +threads +urandom +xml -dlz -geoip -gssapi -ldap -mysql -odbc -postgres -resolvconf -sdb-ldap (-selinux)" emerge --info: Portage 2.1.9.42 (default/linux/amd64/10.0/server, gcc-4.4.5, libc-0-r0, 2.6.34-gentoo-r6-domU x86_64) ================================================================= System uname: Linux-2.6.34-gentoo-r6-domU-x86_64-Intel-R-_Xeon-R-_CPU_X5355_@_2.66GHz-with-gentoo-2.0.2 Timestamp of tree: Tue, 31 May 2011 10:30:01 +0000 app-shells/bash: 4.1_p9 dev-lang/python: 2.7.1-r1, 3.1.3-r1 dev-util/cmake: 2.8.4-r1 sys-apps/baselayout: 2.0.2 sys-apps/openrc: 0.8.2-r1 sys-apps/sandbox: 2.4 sys-devel/autoconf: 2.13, 2.65-r1 sys-devel/automake: 1.5, 1.7.9-r1, 1.9.6-r2, 1.10.3, 1.11.1 sys-devel/binutils: 2.20.1-r1 sys-devel/gcc: 4.4.5 sys-devel/gcc-config: 1.4.1-r1 sys-devel/libtool: 2.2.10 sys-devel/make: 3.82 sys-kernel/linux-headers: 2.6.36.1 sys-libs/glibc: 2.12.2 virtual/os-headers: 0 ACCEPT_KEYWORDS="amd64" ACCEPT_LICENSE="* -@EULA" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-march=native -O3 -pipe" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/share/gnupg/qualified.txt /var/bind" CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/php/apache2-php5.3/ext-active/ /etc/php/cgi-php5.3/ext-active/ /etc/php/cli-php5.3/ext-active/ /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo /etc/texmf/language.dat.d /etc/texmf/language.def.d /etc/texmf/updmap.d /etc/texmf/web2c" CXXFLAGS="-march=native -O2 -pipe" DISTDIR="/usr/portage/distfiles" FEATURES="assume-digests binpkg-logs distlocks fixlafiles fixpackages news parallel-fetch protect-owned sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch" FFLAGS="" GENTOO_MIRRORS="http://distfiles.gentoo.org" LANG="hu" LC_ALL="hu_HU.UTF-8" LDFLAGS="-Wl,-O1 -Wl,--as-needed" LINGUAS="hu en" MAKEOPTS="-j1" PKGDIR="/usr/portage/packages" PORTAGE_CONFIGROOT="/" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --stats --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" SYNC="rsync://rsync.gentoo.org/gentoo-portage" USE="7zip acl amd64 apache2 authfile ban bash-completion bcmath berkdb bzip2 calendar case cgi cli cracklib crypt ctype cxx doc dri examples exif extensions extra extras fastcgi filter fontconfig fortran ftp gd gdbm geoip gif glibc-omitfp gmp gpm hash hpn hvm i18n iconv idn ifsession imap iproute2 ipv6 jadetex jpeg jpeg2k libssh2 lmtp lvm md5sum mktemp mmx modules mudflap multilib mysql mysqli ncurses nls nptl nptlonly nss ogg openmp opensslcrypt pam passwdqc pcntl pcre pdo perl php png posix pppd python python3 quota quotas readline rewrite rrdcgi samba sample sasl sensord session shaper simplexml sitemisc slang sni snmp soap sockets softquota spell sse sse2 ssl subversion suexec svg sysfs sysvipc tcpd threads tidy truetype unicode urandom utils vda vhosts vroot xinetd xml xmldoclet xmlpatterns xmlreader xmlrpc xmlwriter xpm xsl xslt zip zlib" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mmap_emul mulaw multi null plug rate route share shm softvol" APACHE2_MODULES="actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" APACHE2_MPMS="worker" CALLIGRA_FEATURES="braindump flow karbon kexi kpresenter krita tables words" CAMERAS="ptp2" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf superstar2 timing tsip tripmate tnt ubx" INPUT_DEVICES="keyboard mouse evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LINGUAS="hu en" PHP_TARGETS="php5-3" RUBY_TARGETS="ruby18" USERLAND="GNU" VIDEO_CARDS="fbdev glint intel mach64 mga neomagic nouveau nv r128 radeon savage sis tdfx trident vesa via vmware dummy v4l" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account" Unset: CPPFLAGS, CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, PORTDIR_OVERLAY
Sorry for disturbing, first I tought wget implements a direct name resolution instead of gethostbyname(), but it seems the resolver itself is broken. Everything holds what I wrote in this bug, but it seems the problem is inside the (rather old) glibc, and nothing to with wget. Guess i shuld upgrade glibc.
