AcuriouscaseofbrokenDNSresponsesBabakFarrokhiRIPE75AboutmeUnixSA(FreeBSD,Solaris,Linux)since1996IPNetworkingsince1997FreeBSDPortsTeamsince2004Enthusiasticcoder@farrokhiPrologueWhenitcomestonetwork,IalwayshavetrustissuesMostpeopleignorethosestrangenetworkbehaviorsOnlyafewpeopletaketheredpillandgodowntherabbithole.
.
.
ObservationOutgoingSMTPfailsduetoMXlookupfailuresonlycertaindomains(e.
g.
twitter.
com)Localresolverreturns"incorrect"responsePublicResolver(e.
g.
Google)alsoreturnedincorrectresponseIneededtolookdeeperintothisDowntherabbithole.
.
.
StrangeresponsesfrompublicresolversThisisnotwhatIexpectedtogetfromapublicresolver:%dig+short-tAtwitter.
com@8.
8.
8.
810.
10.
34.
34%dig+short-tAripe.
net@8.
8.
8.
8193.
0.
6.
139%dig-tMXtwitter.
com@8.
8.
8.
8;;Gotbadpacket:badlabeltype45bytes40108180000100010000000007747769twi7474657203636f6d00000c0001c00c00tter.
com.
.
.
.
.
.
.
.
0c000100000379000341414100.
.
.
.
.
.
y.
.
AAA.
NeedtotakeacloserlookNotobviousatfirstglance,buttimedeltaisstrange.
.
.
%tcpdump-ttt-c2-nqrripe.
pcapreadingfromPCAP-NGfileripe.
pcap00:00:00.
000000IP192.
168.
0.
132.
53425>8.
8.
8.
8.
53:UDP,length2700:00:00.
138933IP8.
8.
8.
8.
53>192.
168.
0.
132.
53425:UDP,length75%tcpdump-ttt-c2-nqrtwitter.
pcapreadingfromPCAP-NGfiletwitter.
pcap00:00:00.
000000IP192.
168.
0.
132.
58418>8.
8.
8.
8.
53:UDP,length2900:00:00.
028077IP8.
8.
8.
8.
53>192.
168.
0.
132.
58418:UDP,length45dnsping-AnewtoolisbornStartedasahumblePythonscripttosolvemyownproblemNotintendedtore-inventthewheelSimilaruserexperienceasthelegacyPING%.
/dnsping.
py-s8.
8.
8.
8-c3ripe.
netdnsping.
pyDNS:8.
8.
8.
8:53,hostname:ripe.
net,rdatatype:A32bytesfrom8.
8.
8.
8:seq=0time=200.
371ms32bytesfrom8.
8.
8.
8:seq=1time=217.
320ms32bytesfrom8.
8.
8.
8:seq=2time=236.
644ms---8.
8.
8.
8dnspingstatistics---3requeststransmitted,3responsesreceived,0%lostmin=200.
371ms,avg=218.
112ms,max=236.
644ms,stddev=18.
149msICMPvsDNSResponseTimes%ping-q-c108.
8.
8.
8PING8.
8.
8.
8(8.
8.
8.
8):56databytes---8.
8.
8.
8pingstatistics---10packetstransmitted,10packetsreceived,0.
0%packetlossround-tripmin/avg/max/stddev=124.
237/155.
044/227.
499/31.
464ms%.
/dnsping.
py-q-s8.
8.
8.
8-c3twitter.
comdnsping.
pyDNS:8.
8.
8.
8:53,hostname:twitter.
com,rdatatype:A---8.
8.
8.
8dnspingstatistics---3requeststransmitted,3responsesreceived,0%lostmin=12.
934ms,avg=21.
355ms,max=29.
425ms,stddev=8.
251msFirstanomalyDifferentdomainnamesbeingtreateddifferentlyAroguenameserverimpersonatingasGoogleResolverTheroguenameserverisclosetome(givenresponsetimes)WhereisitAndhowcanIfindoutdnstraceroute:TraceroutetoolforDNSprotocolSimilartolegacytraceroute,butforDNSprotocolSendoutactualDNSqueriesandexpectaresponseUsingTTLtricktomapthejourneyCouldnotuselegacytraceroutewithUDPprobesThetrafficredirectionisbasedonDNS"payload"RealvsRogueDNSServers%.
/dnstraceroute.
py-s8.
8.
8.
8ripe.
netdnstraceroute.
pyDNS:8.
8.
8.
8:53,hostname:ripe.
net,rdatatype:A1192.
168.
0.
1(192.
168.
0.
1)3.
912ms2*3192.
168.
10.
105(192.
168.
10.
105)15.
792ms4172.
17.
2.
1(172.
17.
2.
1)17.
063ms5172.
17.
2.
9(172.
17.
2.
9)11.
245ms6172.
19.
18.
5(172.
19.
18.
5)24.
862ms7172.
19.
17.
2(172.
19.
17.
2)18.
972ms810.
201.
177.
41(10.
201.
177.
41)13.
261ms910.
10.
53.
190(10.
10.
53.
190)14.
240ms10185.
100.
209.
117(185.
100.
209.
117)176.
592ms11*12de-cix.
fra.
google.
com(80.
81.
192.
108)152.
757ms13108.
170.
251.
193(108.
170.
251.
193)90.
347ms14google-public-dns-a.
google.
com(8.
8.
8.
8)185.
401ms%.
/dnstraceroute.
py-s8.
8.
8.
8twitter.
comdnstraceroute.
pyDNS:8.
8.
8.
8:53,hostname:twitter.
com,rdatatype:A1192.
168.
0.
1(192.
168.
0.
1)3.
160ms2*3192.
168.
10.
105(192.
168.
10.
105)5.
985ms4172.
17.
2.
1(172.
17.
2.
1)8.
535ms5172.
17.
2.
9(172.
17.
2.
9)20.
617ms6172.
19.
18.
5(172.
19.
18.
5)7.
823ms7*8*9google-public-dns-a.
google.
com(8.
8.
8.
8)19.
557msBacktothecaseofbrokenMXRoguenameserveralsoreturns"broken"responsesOnlytocertaintypeofqueries(e.
g.
MX)%dig-tMXtwitter.
com@8.
8.
8.
8;;Gotbadpacket:badlabeltype45bytes40108180000100010000000007747769twi7474657203636f6d00000c0001c00c00tter.
com.
.
.
.
.
.
.
.
0c000100000379000341414100.
.
.
.
.
.
y.
.
AAA.
Lookingatpacketsagain.
.
.
ResponsetoMXrequestismalformedServerrespondedwithPTRresponseRDLENGTHis3butRDATAfieldcontains4bytesAdditionalbytewasalwaysNULLSeemslikeabugincodeQueriedtop10,000domainnames[1],received139brokenresponses[2]UncoveringtherougeresolveraddressQueryTXTrecordfrommaxmind.
test-ipv6.
comIttellsyouthepublicaddressofyourresolverTheaddressshouldbelongtoGoogle(AS15169)AnythingelsemeansMITMUsingRIPEAtlastoseeifthisisaregularpractice%dig+short-tTXTmaxmind.
test-ipv6.
com@8.
8.
4.
4"ip='74.
125.
74.
14'as='15169'isp='Google'country='FI'"IsitjustmeLet'saskRIPEAtlas500Probesworldwide-484Replied(DNS/UDP/IPv4)475Good(Req.
fromGoogleaddressspace)~98%9Bad(Req.
fromnon-Googleaddressspace)~2%Same500probes-484Replied(DNS/TCP/IPv4)479Good~99%5Bad~1%ThelogicbehindDNStrafficredirectionWhatisthemotivationTherearemainlytworeasons:1.
Privacyprotection(TheGood)Preventsendingrequesttousehaveyourend-pointIPaddressasitssourceaddressFilteroutmalwareslookingfortheirC&C2.
DNSbasedserviceredirection(TheEvil)RestrictyouraccessRedirectyourtrafficCountermeasuresForcelocalresolvertouseTCPDNSCrypt(dnscrypt.
org)OpenDNSsupportsit,desktopclientsavailableDNSoverTLS/DTLS(RFC7858and8094)DNSPrivacyProject(dnsprivacy.
org)offerstutorials,tools,recommendationsandtestserversDNSSECFromtop100domainnamesonly2ofthemaresigned[3]WhatiftheroguenameserverdoesnotvalidateDNSSECFinalwordsDon'ttrustapublicDNSresolver,useyourownThereain'tnosuchthingasafreelunch(TANSTAAFL)Stubresolversareeasytosetupanduse(e.
g.
Stubby)Don'ttrustyourupstream,encryptasmuchaspossibleDNScontainsimportantinformationAsperRFC7258:"PervasiveMonitoringIsanAttack"Toolsofthetradednsping,dnstracerouteanddnsevalarepartof"dnsdiagtoolkit"onGitHub[4]LookingforfeedbackandideasfromcommunityCombiningwithothertools(e.
g.
RIPEAtlas)toperformmorecomplexbehavioranalysisSuggestion:dnstracerouteinRIPEAtlasprobesQuestionsResources[1]https://github.
com/opendns/public-domain-lists[2]https://gist.
github.
com/farrokhi/0b56ae06813391be9164[3]https://gist.
github.
com/farrokhi/1d9de9df5877aaf9c42fc14412a4b0f8[4]https://github.
com/farrokhi/dnsdiagAlsomyarticlesonRIPELabsdiscussionthesameissue:https://labs.
ripe.
net/Members/babak_farrokhi
Hostodo又发布了几款针对7月4日美国独立日的优惠套餐(Independence Day Super Sale),均为年付,基于KVM架构,采用NVMe硬盘,最低13.99美元起,可选拉斯维加斯或者迈阿密机房。这是一家成立于2014年的国外VPS主机商,主打低价VPS套餐且年付为主,基于OpenVZ和KVM架构,产品性能一般,支持使用PayPal或者支付宝等付款方式。商家客服响应也比较一般,推...
LightNode是一家位于香港的VPS服务商.提供基于KVM虚拟化技术的VPS.在提供全球常见节点的同时,还具备东南亚地区、中国香港等边缘节点.满足开发者建站,游戏应用,外贸电商等应用场景的需求。新用户注册充值就送,最高可获得20美元的奖励金!成为LightNode的注册用户后,还可以获得属于自己的邀请链接。通过你的邀请链接带来的注册用户,你将直接获得该用户的消费的10%返佣,永久有效!平台目前...
目前云服务器市场竞争是相当的大的,比如我们在年中活动中看到各大服务商都找准这个噱头的活动发布各种活动,有的甚至就是平时的活动价格,只是换一个说法而已。可见这个行业确实竞争很大,当然我们也可以看到很多主机商几个月就消失,也有看到很多个人商家捣鼓几个品牌然后忽悠一圈跑路的。当然,个人建议在选择服务商的时候尽量选择老牌商家,这样性能更为稳定一些。近期可能会准备重新整理Vultr商家的一些信息和教程。以前...
traceroute为你推荐
比赛winrarbasedcss支持ipad支持ipadphotoshop技术什么是ps技术photoshop技术什么是ps技术css下拉菜单css下拉菜单代码tcpip上的netbios网络连接详细信息上的netbios over tcpip是什么意思?x-routerX-TRAlL是什么意思联通iphone4iphone4想换联通的卡 是普通联通的卡都能开通3G么 还是得换联通3G卡 联通都有什么套餐 我是北京的
虚拟主机推荐 绍兴服务器租用 视频空间租用 联通vps 贝锐花生壳域名 kdata 淘宝双十一2018 嘟牛 微信收钱 百度云1t 常州联通宽带 如何建立邮箱 web服务器是什么 iki 广东服务器托管 沈阳idc 优惠服务器 zencart安装 主机托管 英国伦敦发生爆炸 更多