2011/2/22 Florian Weimer <fwei...@bfk.de>: > * Drunkard Zhang: > >> My capture command: tcpdump -s 0 -nnnvvv -w 360.cn-`date +%Y%m%d`.pcap >> udp port 53 >> >> 17:59:36 ~ $ dig +nocmd speedtest.360.cn @211.161.192.1 +multiline >> +noall +answer >> speedtest.360.cn. 215 IN CNAME speedtest.360.cn.cloudcdn.net. >> speedtest.360.cn.cloudcdn.net. 325 IN CNAME cloud010005.cachecn.com. >> cloud010005.cachecn.com. 368 IN A 61.155.141.28 >> >> but bind just resolved cloud010005.cachecn.com again. > > With a cold cache, I see this: > > [1au] A? speedtest.360.cn. ar: . OPT UDPsize=4096 OK (45) > [1au] A? speedtest.360.cn.cloudcdn.net. ar: . OPT UDPsize=4096 OK (58) > [1au] A? cloud010005.cachecn.com. ar: . OPT UDPsize=4096 OK (52) > > I suspect that the middle CNAME is still in cache in your case. > I don't think so. I started named with: "named -u named -n1 -g -d 3" on a test machine, then "tcpdump -s 0 -nnnvvv udp port 53" in another window, and "dig +nocmd speedtest.360.cn @211.161.192.146 +multiline +noall +answer" in another window. I did the test as clean as possible.
Below is all got by tcpdump, pretty similar with pcap file in first mail. [Added blank lines between packets by hand] ~ # tcpdump -s 0 -nnnvvv udp port 53 tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes 20:43:08.393967 IP (tos 0x0, ttl 47, id 1482, offset 0, flags [none], proto UDP (17), length 62) 58.41.157.204.59988 > 211.161.192.146.53: [udp sum ok] 6096+ A? speedtest.360.cn. (34) 20:43:08.396078 IP (tos 0x0, ttl 64, id 45821, offset 0, flags [none], proto UDP (17), length 73) 211.161.192.146.14231 > 211.161.192.1.53: [bad udp cksum 6d1a!] 49635+ [1au] A? speedtest.360.cn. ar: . OPT UDPsize=4096 OK (45) 20:43:08.396380 IP (tos 0x0, ttl 64, id 39052, offset 0, flags [none], proto UDP (17), length 56) 211.161.192.146.50308 > 192.228.79.201.53: [bad udp cksum 2cca!] 37786 [1au] NS? . ar: . OPT UDPsize=4096 OK (28) 20:43:08.398608 IP (tos 0x0, ttl 58, id 44814, offset 0, flags [none], proto UDP (17), length 377) 211.161.192.1.53 > 211.161.192.146.14231: [udp sum ok] 49635 q: A? speedtest.360.cn. 3/8/5 speedtest.360.cn. CNAME speedtest.360.cn.cloudcdn.net., speedtest.360.cn.cloudcdn.net. CNAME cloud010005.cachecn.com., cloud010005.cachecn.com. A 61.155.141.28 ns: cachecn.com. NS ns8.cachecn.com., cachecn.com. NS ns4.cachecn.com., cachecn.com. NS ns7.cachecn.com., cachecn.com. NS ns1.cachecn.com., cachecn.com. NS ns5.cachecn.com., cachecn.com. NS ns3.cachecn.com., cachecn.com. NS ns6.cachecn.com., cachecn.com. NS ns2.cachecn.com. ar: ns5.cachecn.com. A 211.100.19.162, ns6.cachecn.com. A 202.106.196.105, ns7.cachecn.com. A 222.73.28.254, ns8.cachecn.com. A 122.226.213.156, . OPT UDPsize=4096 OK (349) 20:43:08.399516 IP (tos 0x0, ttl 64, id 6525, offset 0, flags [none], proto UDP (17), length 80) 211.161.192.146.31420 > 192.203.230.10.53: [bad udp cksum a4ab!] 43801 [1au] A? cloud010005.cachecn.com. ar: . OPT UDPsize=4096 OK (52) 20:43:08.688506 IP (tos 0x0, ttl 43, id 32537, offset 0, flags [none], proto UDP (17), length 753) 192.203.230.10.53 > 211.161.192.146.31420: [udp sum ok] 43801- q: A? cloud010005.cachecn.com. 0/15/16 ns: com. NS b.gtld-servers.net., com. NS c.gtld-servers.net., com. NS a.gtld-servers.net., com. NS k.gtld-servers.net., com. NS l.gtld-servers.net., com. NS j.gtld-servers.net., com. NS m.gtld-servers.net., com. NS i.gtld-servers.net., com. NS g.gtld-servers.net., com. NS f.gtld-servers.net., com. NS e.gtld-servers.net., com. NS d.gtld-servers.net., com. NS h.gtld-servers.net., com. NSEC, com. RRSIG ar: a.gtld-servers.net. A 192.5.6.30, a.gtld-servers.net. AAAA 2001:503:a83e::2:30, b.gtld-servers.net. A 192.33.14.30, b.gtld-servers.net. AAAA 2001:503:231d::2:30, c.gtld-servers.net. A 192.26.92.30, d.gtld-servers.net. A 192.31.80.30, e.gtld-servers.net. A 192.12.94.30, f.gtld-servers.net. A 192.35.51.30, g.gtld-servers.net. A 192.42.93.30, h.gtld-servers.net. A 192.54.112.30, i.gtld-servers.net. A 192.43.172.30, j.gtld-servers.net. A 192.48.79.30, k.gtld-servers.net. A 192.52.178.30, l.gtld-servers.net. A 192.41.162.30, m.gtld-servers.net. A 192.55.83.30, . OPT UDPsize=4096 OK (725) 20:43:08.689155 IP (tos 0x0, ttl 64, id 4592, offset 0, flags [none], proto UDP (17), length 80) 211.161.192.146.56785 > 192.35.51.30.53: [bad udp cksum 7b72!] 59478 [1au] A? cloud010005.cachecn.com. ar: . OPT UDPsize=4096 OK (52) 20:43:08.741174 IP (tos 0x0, ttl 43, id 13825, offset 0, flags [none], proto UDP (17), length 857) 192.228.79.201.53 > 211.161.192.146.50308: [udp sum ok] 37786*- q: NS? . 14/0/22 . NS a.root-servers.net., . NS i.root-servers.net., . NS m.root-servers.net., . NS l.root-servers.net., . NS d.root-servers.net., . NS e.root-servers.net., . NS g.root-servers.net., . NS b.root-servers.net., . NS c.root-servers.net., . NS f.root-servers.net., . NS j.root-servers.net., . NS k.root-servers.net., . NS h.root-servers.net., . RRSIG ar: a.root-servers.net. A 198.41.0.4, b.root-servers.net. A 192.228.79.201, c.root-servers.net. A 192.33.4.12, d.root-servers.net. A 128.8.10.90, e.root-servers.net. A 192.203.230.10, f.root-servers.net. A 192.5.5.241, g.root-servers.net. A 192.112.36.4, h.root-servers.net. A 128.63.2.53, i.root-servers.net. A 192.36.148.17, j.root-servers.net. A 192.58.128.30, k.root-servers.net. A 193.0.14.129, l.root-servers.net. A 199.7.83.42, m.root-servers.net. A 202.12.27.33, a.root-servers.net. AAAA 2001:503:ba3e::2:30, f.root-servers.net. AAAA 2001:500:2f::f, h.root-servers.net. AAAA 2001:500:1::803f:235, i.root-servers.net. AAAA 2001:7fe::53, j.root-servers.net. AAAA 2001:503:c27::2:30, k.root-servers.net. AAAA 2001:7fd::1, l.root-servers.net. AAAA 2001:500:3::42, m.root-servers.net. AAAA 2001:dc3::35, . OPT UDPsize=4096 OK (829) 20:43:09.188375 IP (tos 0x0, ttl 42, id 57476, offset 0, flags [none], proto UDP (17), length 216) 192.35.51.30.53 > 211.161.192.146.56785: [udp sum ok] 59478- q: A? cloud010005.cachecn.com. 0/4/5 ns: cachecn.com. NS ns1.cachecn.com., cachecn.com. NS ns2.cachecn.com., cachecn.com. NS ns4.cachecn.com., cachecn.com. NS ns3.cachecn.com. ar: ns1.cachecn.com. A 211.100.19.166, ns2.cachecn.com. A 61.152.94.167, ns4.cachecn.com. A 60.31.215.206, ns3.cachecn.com. A 210.75.240.15, . OPT UDPsize=512 OK (188) 20:43:09.188756 IP (tos 0x0, ttl 64, id 11374, offset 0, flags [none], proto UDP (17), length 80) 211.161.192.146.43751 > 211.100.19.166.53: [bad udp cksum 1a67!] 16144 [1au] A? cloud010005.cachecn.com. ar: . OPT UDPsize=4096 OK (52) 20:43:09.229260 IP (tos 0x0, ttl 48, id 65156, offset 0, flags [none], proto UDP (17), length 368) 211.100.19.166.53 > 211.161.192.146.43751: [udp sum ok] 16144*- q: A? cloud010005.cachecn.com. 1/8/9 cloud010005.cachecn.com. A 112.90.216.14 ns: cachecn.com. NS ns5.cachecn.com., cachecn.com. NS ns2.cachecn.com., cachecn.com. NS ns4.cachecn.com., cachecn.com. NS ns6.cachecn.com., cachecn.com. NS ns7.cachecn.com., cachecn.com. NS ns3.cachecn.com., cachecn.com. NS ns1.cachecn.com., cachecn.com. NS ns8.cachecn.com. ar: ns1.cachecn.com. A 211.100.19.166, ns2.cachecn.com. A 61.152.94.167, ns3.cachecn.com. A 210.75.240.15, ns4.cachecn.com. A 60.31.215.206, ns5.cachecn.com. A 211.100.19.162, ns6.cachecn.com. A 202.106.196.105, ns7.cachecn.com. A 222.73.28.254, ns8.cachecn.com. A 122.226.213.156, . OPT UDPsize=4096 OK (340) 20:43:09.229694 IP (tos 0x0, ttl 64, id 62111, offset 0, flags [none], proto UDP (17), length 366) 211.161.192.146.53 > 58.41.157.204.59988: [bad udp cksum 1f39!] 6096 q: A? speedtest.360.cn. 3/8/4 speedtest.360.cn. CNAME speedtest.360.cn.cloudcdn.net., speedtest.360.cn.cloudcdn.net. CNAME cloud010005.cachecn.com., cloud010005.cachecn.com. A 112.90.216.14 ns: cachecn.com. NS ns3.cachecn.com., cachecn.com. NS ns4.cachecn.com., cachecn.com. NS ns5.cachecn.com., cachecn.com. NS ns6.cachecn.com., cachecn.com. NS ns7.cachecn.com., cachecn.com. NS ns8.cachecn.com., cachecn.com. NS ns1.cachecn.com., cachecn.com. NS ns2.cachecn.com. ar: ns5.cachecn.com. A 211.100.19.162, ns6.cachecn.com. A 202.106.196.105, ns7.cachecn.com. A 222.73.28.254, ns8.cachecn.com. A 122.226.213.156 (338) ^C 12 packets captured 12 packets received by filter 0 packets dropped by kernel ~ # named -v BIND 9.7.2-P3 ~ # And the dig result: 20:50:22 ~ $ dig +nocmd speedtest.360.cn @211.161.192.146 +multiline +noall +answer speedtest.360.cn. 1098 IN CNAME speedtest.360.cn.cloudcdn.net. speedtest.360.cn.cloudcdn.net. 55 IN CNAME cloud010005.cachecn.com. cloud010005.cachecn.com. 600 IN A 112.90.216.14 TTL in first two lines isn't orginal value, so these should be from upstream DNS 211.161.192.1 . _______________________________________________ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
