From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10261 invoked by alias); 29 Jun 2012 00:04:53 -0000 Received: (qmail 10238 invoked by uid 22791); 29 Jun 2012 00:04:50 -0000 X-SWARE-Spam-Status: No, hits=-3.0 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from localhost (HELO sourceware.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 29 Jun 2012 00:04:34 +0000 From: "jvb127 at gmail dot com" 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 X-Bugzilla-Reason: CC X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: glibc X-Bugzilla-Component: network X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: jvb127 at gmail dot com X-Bugzilla-Status: NEW X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: unassigned at sourceware dot org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Message-ID: X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Mailing-List: contact glibc-bugs-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: glibc-bugs-owner@sourceware.org X-SW-Source: 2012-06/txt/msg00330.txt.bz2 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.