Hoje tive um problema em que minha implantação nos meus servidores de aplicativos não pôde ser concluída devido a problemas de conexão com o github.
Percebi que, quando realizo uma pesquisa de DNS do github.com usando servidores DNS do Google, recebo os endereços IP "corretos / antigos", que também são documentados oficialmente pelo guthub AQUI .
root@server# host github.com 8.8.8.8
Using domain server:
Name: 8.8.8.8
Address: 8.8.8.8#53
Aliases:
github.com has address 192.30.253.112
github.com has address 192.30.253.113
github.com mail is handled by 10 ALT4.ASPMX.L.GOOGLE.com.
github.com mail is handled by 10 ALT3.ASPMX.L.GOOGLE.com.
github.com mail is handled by 5 ALT1.ASPMX.L.GOOGLE.com.
github.com mail is handled by 1 ASPMX.L.GOOGLE.com.
github.com mail is handled by 5 ALT2.ASPMX.L.GOOGLE.com.
No entanto, quando uso meus servidores DNS do provedor de hospedagem, obtenho resultados diferentes:
root@server# host github.com 213.133.98.98
Using domain server:
Name: 213.133.98.98
Address: 213.133.98.98#53
Aliases:
github.com has address 18.195.85.27
github.com has address 35.159.8.160
github.com has address 18.194.104.89
github.com mail is handled by 1 ASPMX.L.GOOGLE.com.
github.com mail is handled by 10 ALT4.ASPMX.L.GOOGLE.com.
github.com mail is handled by 10 ALT3.ASPMX.L.GOOGLE.com.
github.com mail is handled by 5 ALT1.ASPMX.L.GOOGLE.com.
github.com mail is handled by 5 ALT2.ASPMX.L.GOOGLE.com.
Quando entrei em contato com meu provedor para saber por que eles estão atendendo a esses resultados, eles afirmaram que os registros mudaram. Na verdade, isso parece estar correto desde quando eu executar um rastreamento de githubs dns registros usando novamente o servidor google dns eu recebo os "novos" registros:
root@server# dig github.com +trace @8.8.8.8
...
text omitted
...
github.com. 172800 IN NS ns-520.awsdns-01.net.
github.com. 172800 IN NS ns-421.awsdns-52.com.
github.com. 172800 IN NS ns-1707.awsdns-21.co.uk.
github.com. 172800 IN NS ns-1283.awsdns-32.org.
CK0POJMG874LJREF7EFN8430QVIT8BSM.com. 86400 IN NSEC3 1 1 0 - CK0Q1GIN43N1ARRC9OSM6QPQR81H5M9A NS SOA RRSIG DNSKEY NSEC3PARAM
CK0POJMG874LJREF7EFN8430QVIT8BSM.com. 86400 IN RRSIG NSEC3 8 2 86400 20171215054800 20171208043800 11324 com. mBRl9D0i8jmeYbtZzR527TfVtbq2x6RSECv23chq0usVGZzVCQz5BYbV JaWeaQ1QWRuTWz3snYFkQBaG7SLQbipDEaVaMgjQ9qnHitJxwzEYPTn0 mT5nweDT+IVqP3NpppB748HAr9IiqqNOar1IyQokv3S59E9cK+s1W3V0 Mik=
4KB3QDAGSO6KO9JK2O5F2FO8F4C5FTA2.com. 86400 IN NSEC3 1 1 0 - 4KB4PTQQ5CTA7POCTGM7RUFC8B1RKTEU NS DS RRSIG
4KB3QDAGSO6KO9JK2O5F2FO8F4C5FTA2.com. 86400 IN RRSIG NSEC3 8 2 86400 20171212052031 20171205041031 11324 com. DmETcOQrFR+iFYhCH4xGJT+khPaTF4Ay50o+FrdpBvRTOPT9WTFf1wOF Ew3cQlBGHdwS2TiT+tLsUlshkmiKZpdH753Lac9Z0ZBU6fcB/PWOwMQX NGPWwYZFrGb8I2QsEvQreBM+WcftfdHGXHn5ziUx8phz1lbJuQXhVYyl LBk=
;; Received 840 bytes from 192.43.172.30#53(i.gtld-servers.net) in 17 ms
github.com. 60 IN A 18.195.85.27
github.com. 60 IN A 18.194.104.89
github.com. 60 IN A 35.159.8.160
github.com. 900 IN NS ns-1283.awsdns-32.org.
github.com. 900 IN NS ns-1707.awsdns-21.co.uk.
github.com. 900 IN NS ns-421.awsdns-52.com.
github.com. 900 IN NS ns-520.awsdns-01.net.
github.com. 900 IN NS ns1.p16.dynect.net.
github.com. 900 IN NS ns2.p16.dynect.net.
github.com. 900 IN NS ns3.p16.dynect.net.
github.com. 900 IN NS ns4.p16.dynect.net.
;; Received 307 bytes from 205.251.198.171#53(ns-1707.awsdns-21.co.uk) in 12 ms
Por que, quando estou usando o github.com usando o google DNS, ele retruza "ips antigos", mas quando eu uso um rastreamento dns, ele retorna os novos? O dns do google retornou os registros armazenados em cache (mesmo um dia depois)?
Por outro lado, o github mudaria seus endereços IP sem notificar ninguém? Sua documentação não menciona esses "novos" endereços IP e, tanto quanto eu pesquisei, sempre que eles fizeram tal mudança, eles também postaram em seu blog.