DNS resolution question
Bruce Ferrell
bferrell at baywinds.org
Wed Dec 24 16:49:04 UTC 2014
On 12/24/2014 06:40 AM, Casey Scott wrote:
> This issue surfaced when I noticed this entry in my servers daily security mail:
>
> Checking for packages with security vulnerabilities:
> pkg: http://vuxml.freebsd.org/freebsd/vuln.xml.bz2: No address record
> pkg: cannot fetch vulnxml file
>
>
> I discovered that the server is not able to resolve vuxml.freebsd.org, or even www.freebsd.org. I'm sure the problem isn't specific to the freebsd.org zone, but that's where I focused my effort. I found that recursive queries failed, however if I directly queried a name server authoritative for freebsd.org (i.e. ns1.isc-sns.net.), the query successfully returned the CNAME.
>
> OS Details:
> FreeBSD mustang 9.3-RELEASE FreeBSD 9.3-RELEASE #0 r271930: Sun Sep 21 19:01:57 PDT 2014 root at mustang:/usr/src/sys/amd64/compile/Server amd64
>
>
> DNS lookup attempt
> *******************************************************************************
> $ dig vuxml.freebsd.org +trace
> ; <<>> DiG 9.9.6-P1 <<>> vuxml.freebsd.org +trace
> ;; global options: +cmd
> . 517326 IN NS e.root-servers.net.
> . 517326 IN NS m.root-servers.net.
> . 517326 IN NS c.root-servers.net.
> . 517326 IN NS d.root-servers.net.
> . 517326 IN NS b.root-servers.net.
> . 517326 IN NS f.root-servers.net.
> . 517326 IN NS g.root-servers.net.
> . 517326 IN NS i.root-servers.net.
> . 517326 IN NS k.root-servers.net.
> . 517326 IN NS l.root-servers.net.
> . 517326 IN NS a.root-servers.net.
> . 517326 IN NS j.root-servers.net.
> . 517326 IN NS h.root-servers.net.
> . 517326 IN RRSIG NS 8 0 518400 20141231050000 20141224040000 22603 . OT3Uv0Krt43V999nh6ky8sK7Uob+Qb+M82BOS0uPTFxq1NL6m2XX7ri3 n/na4QyB/+iGTAlonAMVGyXEO1llrJt6iw7yucBriqy/xuGCwSY5Sllc Y3G7RdzerNgmAhfD2wiCwJPnVuGaD3O5318r2TLrsXdoQwGk7FNWiE1X GBE=
> ;; Received 913 bytes from 192.168.1.1#53(192.168.1.1) in 0 ms
>
> org. 172800 IN NS b2.org.afilias-nst.org.
> org. 172800 IN NS a2.org.afilias-nst.info.
> org. 172800 IN NS d0.org.afilias-nst.org.
> org. 172800 IN NS b0.org.afilias-nst.org.
> org. 172800 IN NS a0.org.afilias-nst.info.
> org. 172800 IN NS c0.org.afilias-nst.info.
> org. 86400 IN DS 21366 7 2 96EEB2FFD9B00CD4694E78278B5EFDAB0A80446567B69F634DA078F0 D90F01BA
> org. 86400 IN DS 21366 7 1 E6C1716CFB6BDC84E84CE1AB5510DAC69173B5B2
> org. 86400 IN RRSIG DS 8 1 86400 20141231050000 20141224040000 22603 . IjE3Yi3yF8a12dOlLt13Grqs7c2tOXwgyyghAkeqy36N14VrAGxsQMxU RlOE5rYwzeg1cLi55wRxGShNBz0/KU229xWrRNluzLUkbo+eW98E6Fcw nT/DHrIy9J/3zjf6NRC+zUUcQTOJGWAkPF40TqaJGwI0Ag6/p6yxcBJ5 MDM=
> ;; Received 691 bytes from 192.112.36.4#53(g.root-servers.net) in 73 ms
>
> freebsd.org. 86400 IN NS ns2.isc-sns.com.
> freebsd.org. 86400 IN NS ns1.isc-sns.net.
> freebsd.org. 86400 IN NS ns3.isc-sns.info.
> freebsd.org. 86400 IN DS 32659 8 2 AF3B32E46DF2FC32C0110C7D6B808EE73E0411501AFAF9022D3DCD0A FA5B3ACD
> freebsd.org. 86400 IN RRSIG DS 7 2 86400 20150109163356 20141219153356 11112 org. puF07NdtGtOY0uI3d789itchA2dEXz0URwCsckm7vjWoNIhdsMuG6jFc StzdAkvFDiDO/2C3x21spRrb7Y3ioDQpNJL2zJUn2S0L/8ueDbF9wJAT pEfAdMyUwlCQkVM45Ptf98z7iLTWWe2xQBhZZ1OGaPRW+VwKE0rCaz2d 1rg=
> ;; Received 345 bytes from 199.19.53.1#53(c0.org.afilias-nst.info) in 134 ms
>
> ;; connection timed out; no servers could be reached
> *******************************************************************************
>
>
> tcpdump of the query above
> *******************************************************************************
> listening on fxp0, link-type EN10MB (Ethernet), capture size 65535 bytes
> 05:59:36.016640 IP x.x.x.x.54272 > 38.103.2.1.53: 18640 [1au] A? vuxml.freebsd.org. (46)
> 05:59:36.127776 IP 38.103.2.1.53 > x.x.x.x.54272: 18640*- 4/4/11 CNAME wfe0.ysv.freebsd.org., RRSIG, A 8.8.178.110, RRSIG (1464)
> 05:59:38.021067 IP x.x.x.x.52431 > 38.103.2.1.53: 13086 [1au] AAAA? vuxml.freebsd.org. (46)
> 05:59:38.051272 IP x.x.x.x.51125 > 63.243.194.1.53: 16824 [1au] A? vuxml.freebsd.org. (46)
> 05:59:38.081819 IP 63.243.194.1.53 > x.x.x.x.51125: 16824*- 4/4/11 CNAME wfe0.ysv.freebsd.org., RRSIG, A 8.8.178.110, RRSIG (1464)
> 05:59:38.132821 IP 38.103.2.1.53 > x.x.x.x.52431: 13086*- 4/4/11 CNAME wfe0.ysv.freebsd.org., RRSIG, AAAA, RRSIG (1464)
> 05:59:40.056275 IP x.x.x.x.62003 > 63.243.194.1.53: 41954 [1au] AAAA? vuxml.freebsd.org. (46)
> 05:59:40.086597 IP 63.243.194.1.53 > x.x.x.x.62003: 41954*- 4/4/11 CNAME wfe0.ysv.freebsd.org., RRSIG, AAAA, RRSIG (1464)
> 05:59:40.267272 IP x.x.x.x.61416 > 72.52.71.1.53: 32843 [1au] A? vuxml.freebsd.org. (46)
> 05:59:40.297103 IP 72.52.71.1.53 > x.x.x.x.61416: 32843*- 4/4/11 CNAME wfe0.ysv.freebsd.org., RRSIG, A 8.8.178.110, RRSIG (1464)
> 05:59:42.272273 IP x.x.x.x.54674 > 72.52.71.1.53: 2755 [1au] AAAA? vuxml.freebsd.org. (46)
> 05:59:42.302289 IP 72.52.71.1.53 > x.x.x.x.54674: 2755*- 4/4/11 CNAME wfe0.ysv.freebsd.org., RRSIG, AAAA, RRSIG (1464)
> 05:59:42.487277 IP x.x.x.x.54239 > 38.103.2.1.53: 38272 [1au] A? vuxml.freebsd.org. (46)
> 05:59:42.598927 IP 38.103.2.1.53 > x.x.x.x.54239: 38272*- 4/4/11 CNAME wfe0.ysv.freebsd.org., RRSIG, A 8.8.178.110, RRSIG (1464)
> 05:59:44.492281 IP x.x.x.x.59505 > 38.103.2.1.53: 22873 [1au] AAAA? vuxml.freebsd.org. (46)
> 05:59:44.604217 IP 38.103.2.1.53 > x.x.x.x.59505: 22873*- 4/4/11 CNAME wfe0.ysv.freebsd.org., RRSIG, AAAA, RRSIG (1464)
> 05:59:44.722266 IP x.x.x.x.61141 > 63.243.194.1.53: 50828 [1au] A? vuxml.freebsd.org. (46)
> 05:59:44.753517 IP 63.243.194.1.53 > x.x.x.x.61141: 50828*- 4/4/11 CNAME wfe0.ysv.freebsd.org., RRSIG, A 8.8.178.110, RRSIG (1464)
> 05:59:46.727324 IP x.x.x.x.49803 > 63.243.194.1.53: 51222 [1au] AAAA? vuxml.freebsd.org. (46)
> 05:59:46.757577 IP 63.243.194.1.53 > x.x.x.x.49803: 51222*- 4/4/11 CNAME wfe0.ysv.freebsd.org., RRSIG, AAAA, RRSIG (1464)
> 05:59:57.395692 IP x.x.x.x.60149 > 165.254.1.208.53: 31873 [1au] A? e6238.a.akamaiedge.net. (51)
> 05:59:57.404644 IP 165.254.1.208.53 > x.x.x.x.60149: 31873*- 1/0/0 A 96.7.67.53 (56)
> *******************************************************************************
>
> BIND build options
> *******************************************************************************
> # named -V
> BIND 9.9.6-P1 (Extended Support Version) <id:3612d8fb> built by make with '--localstatedir=/var' '--disable-linux-caps' '--disable-symtable' '--with-randomdev=/dev/random' '--with-libxml2=/usr/local' '--disable-filter-aaaa' '--disable-fixed-rrset' '--without-gost' '--without-idn' '--disable-ipv6' '--disable-largefile' '--disable-newstats' '--without-python' '--disable-rpz-nsdname' '--disable-rpz-nsip' '--disable-rrl' '--with-openssl=/usr/local' '--without-gssapi' '--enable-threads' '--sysconfdir=/etc/namedb' '--prefix=/usr' '--mandir=/usr/share/man' '--infodir=/usr/share/info/' '--build=amd64-portbld-freebsd9.3' 'build_alias=amd64-portbld-freebsd9.3' 'CC=cc' 'CFLAGS=-O2 -pipe -march=native -fstack-protector -fno-strict-aliasing' 'LDFLAGS= -Wl,-rpath,/usr/local/lib -fstack-protector' 'LIBS=' 'CPPFLAGS=' 'CPP=cpp'
> compiled by GCC 4.2.1 20070831 patched [FreeBSD]
> using OpenSSL version: OpenSSL 1.0.1j 15 Oct 2014
> using libxml2 version: 2.9.2
> *******************************************************************************
>
> Any idea what's going on here?
>
> Thanks,
> Casey
>
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>
Casey,
think you're getting a correct response.
dig @192.0.2.131 vuxml.freebsd.org
; <<>> DiG 9.9.5-rpz2+rl.14038.05-P1 <<>> @192.0.2.131 vuxml.freebsd.org
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 54956
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 3, ADDITIONAL: 6
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;vuxml.freebsd.org. IN A
;; ANSWER SECTION:
vuxml.freebsd.org. 497 IN CNAME wfe0.ysv.freebsd.org.
wfe0.ysv.freebsd.org. 497 IN A 8.8.178.110
;; AUTHORITY SECTION:
freebsd.org. 497 IN NS ns3.isc-sns.info.
freebsd.org. 497 IN NS ns2.isc-sns.com.
freebsd.org. 497 IN NS ns1.isc-sns.net.
;; ADDITIONAL SECTION:
ns1.isc-sns.net. 2488 IN A 72.52.71.1
ns1.isc-sns.net. 166365 IN AAAA 2001:470:1a::1
ns2.isc-sns.com. 2488 IN A 38.103.2.1
ns3.isc-sns.info. 2488 IN A 63.243.194.1
ns3.isc-sns.info. 79965 IN AAAA 2001:5a0:10::1
;; Query time: 1 msec
;; SERVER: 192.0.2.131#53(192.0.2.131)
;; WHEN: Wed Dec 24 08:28:06 PST 2014
;; MSG SIZE rcvd: 277
Notice in the answer section of my simplified query via my local nameserver, wfe0.ysv.freebsd.org is in the A record. I saw the same response in your query, it was just harder to see.
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