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From: "jvb127 at gmail dot com" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sources.redhat.com Subject: [Bug network/14307] New: getaddrinfo() triggers duplicate DNS requests when answer contains CNAME Date: Fri, 29 Jun 2012 00:04:00 -0000 [thread overview] Message-ID: <bug-14307-131@http.sourceware.org/bugzilla/> (raw) http://sourceware.org/bugzilla/show_bug.cgi?id=14307 Bug #: 14307 Summary: getaddrinfo() triggers duplicate DNS requests when answer contains CNAME Product: glibc Version: unspecified Status: NEW Severity: normal Priority: P2 Component: network AssignedTo: unassigned@sourceware.org ReportedBy: jvb127@gmail.com Classification: Unclassified Created attachment 6493 --> http://sourceware.org/bugzilla/attachment.cgi?id=6493 Packet capture illustrating duplicate (redundant) DNS requests I noticed spurious DNS requests on the network, and traced them down to getaddrinfo() calls (e.g. using wget). This occurs on a Fedora 16 machine with latest glibc, as well as a CentOS machine with older versions To reproduce, perform the following in 2 consoles: $tcpdump -v -n -i eth0 udp port 53 -w getaddr.pcap $wget -4 http://www.gmail.com/ Result: reading from file ./getaddr.pcap, link-type EN10MB (Ethernet) 17:59:38.263471 IP 192.168.1.9.54553 > 8.8.8.8.domain: 32628+ A? www.gmail.com. (31) 17:59:38.313021 IP 8.8.8.8.domain > 192.168.1.9.54553: 32628 4/0/0 CNAME mail.google.com., CNAME googlemail.l.google.com., A 74.125.226.22, A 74.125.226.21 (116) 17:59:38.313311 IP 192.168.1.9.57920 > 8.8.8.8.domain: 44145+ A? www.gmail.com. (31) 17:59:38.367738 IP 8.8.8.8.domain > 192.168.1.9.57920: 44145 4/0/0 CNAME mail.google.com., CNAME googlemail.l.google.com., A 74.125.226.22, A 74.125.226.21 (116) 17:59:38.476300 IP 192.168.1.9.50993 > 8.8.8.8.domain: 25319+ A? mail.google.com. (33) 17:59:38.561056 IP 8.8.8.8.domain > 192.168.1.9.50993: 25319 3/0/0 CNAME googlemail.l.google.com., A 74.125.226.21, A 74.125.226.22 (92) 17:59:38.561306 IP 192.168.1.9.54508 > 8.8.8.8.domain: 35020+ A? mail.google.com. (33) 17:59:38.610485 IP 8.8.8.8.domain > 192.168.1.9.54508: 35020 3/0/0 CNAME googlemail.l.google.com., A 74.125.226.21, A 74.125.226.22 (92) 17:59:38.716233 IP 192.168.1.9.59783 > 8.8.8.8.domain: 48556+ A? accounts.google.com. (37) 17:59:38.765100 IP 8.8.8.8.domain > 192.168.1.9.59783: 48556 2/0/0 CNAME accounts.l.google.com., A 209.85.225.84 (78) 17:59:38.765348 IP 192.168.1.9.41685 > 8.8.8.8.domain: 24558+ A? accounts.google.com. (37) 17:59:38.819577 IP 8.8.8.8.domain > 192.168.1.9.41685: 24558 2/0/0 CNAME accounts.l.google.com., A 209.85.225.84 (78) -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.
next reply other threads:[~2012-06-29 0:04 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-06-29 0:04 jvb127 at gmail dot com [this message] 2012-06-29 6:05 ` [Bug network/14307] " jvb127 at gmail dot com 2012-06-29 6:10 ` [Bug network/14307] getaddrinfo() sends superfluous DNS requests in x86_64 programs " jvb127 at gmail dot com 2012-06-29 11:10 ` siddhesh at redhat dot com 2012-06-29 12:30 ` siddhesh at redhat dot com 2012-06-29 16:06 ` [Bug network/14307] getaddrinfo() sends superfluous DNS requests in x86_64 programs for certain hostnames jvb127 at gmail dot com 2012-06-30 2:23 ` jvb127 at gmail dot com 2012-06-30 3:16 ` jvb127 at gmail dot com 2012-06-30 5:35 ` jvb127 at gmail dot com 2012-06-30 15:09 ` jvb127 at gmail dot com 2012-07-02 2:22 ` siddhesh at redhat dot com 2012-07-12 6:05 ` siddhesh at redhat dot com 2014-02-16 19:32 ` jackie.rosen at hushmail dot com 2014-05-28 19:42 ` schwab at sourceware dot org 2014-06-18 4:31 ` fweimer at redhat dot com
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