====== DNS ======

Quelques outils dns

  apt install dnsutils

Ce paquet fournit divers programmes clients reliés à DNS, qui sont dérivés de l'arbre source de BIND.
  * dig : effectue des requêtes DNS de différentes façons
  * nslookup : ancienne façon de procéder
  * nsupdate : fait des mises à jour dynamiques

<code>
dig google.fr

</code>

Google propose un site web comme interface avec dig => https://toolbox.googleapps.com/apps/dig

Commande de base, utilise votre config dns local
<code>
$ dig google.com

; <<>> DiG 9.11.3-1ubuntu1.11-Ubuntu <<>> google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 47060
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;google.com.			IN	A

;; ANSWER SECTION:
google.com.		264	IN	A	216.58.209.238

;; Query time: 7 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Tue Mar 10 16:44:40 CET 2020
;; MSG SIZE  rcvd: 55
</code>

Questionner un autre serveur DNS
<code>
$ dig google.com @8.8.8.8

; <<>> DiG 9.11.3-1ubuntu1.11-Ubuntu <<>> google.com @8.8.8.8
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 26450
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;google.com.			IN	A

;; ANSWER SECTION:
google.com.		299	IN	A	216.58.204.110

;; Query time: 24 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Tue Mar 10 16:44:44 CET 2020
;; MSG SIZE  rcvd: 55
</code>
Consulter les NS
<code>
$ dig NS google.com

; <<>> DiG 9.11.3-1ubuntu1.11-Ubuntu <<>> NS google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 25987
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;google.com.			IN	NS

;; ANSWER SECTION:
google.com.		14416	IN	NS	ns3.google.com.
google.com.		14416	IN	NS	ns4.google.com.
google.com.		14416	IN	NS	ns1.google.com.
google.com.		14416	IN	NS	ns2.google.com.

;; Query time: 117 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Tue Mar 10 16:45:00 CET 2020
;; MSG SIZE  rcvd: 111
</code>

Renvoie le PTR
<code>
$ dig -x google.com

; <<>> DiG 9.11.3-1ubuntu1.11-Ubuntu <<>> -x google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 43376
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;com.google.in-addr.arpa.	IN	PTR

;; Query time: 170 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Tue Mar 10 16:45:07 CET 2020
;; MSG SIZE  rcvd: 52
</code>
Renvoie tous les type de record enregistré dans le DNS
<code>
$ dig ANY google.com

; <<>> DiG 9.11.3-1ubuntu1.11-Ubuntu <<>> ANY google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30603
;; flags: qr rd ra; QUERY: 1, ANSWER: 18, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;google.com.			IN	ANY

;; ANSWER SECTION:
google.com.		233	IN	A	216.58.209.238
google.com.		14405	IN	NS	ns4.google.com.
google.com.		14405	IN	NS	ns1.google.com.
google.com.		14405	IN	NS	ns2.google.com.
google.com.		14405	IN	NS	ns3.google.com.
google.com.		59	IN	SOA	ns1.google.com. dns-admin.google.com. 299797304 900 900 1800 60
google.com.		599	IN	MX	20 alt1.aspmx.l.google.com.
google.com.		599	IN	MX	40 alt3.aspmx.l.google.com.
google.com.		599	IN	MX	50 alt4.aspmx.l.google.com.
google.com.		599	IN	MX	30 alt2.aspmx.l.google.com.
google.com.		599	IN	MX	10 aspmx.l.google.com.
google.com.		299	IN	TXT	"docusign=1b0a6754-49b1-4db5-8540-d2c12664b289"
google.com.		299	IN	TXT	"v=spf1 include:_spf.google.com ~all"
google.com.		3599	IN	TXT	"globalsign-smime-dv=CDYX+XFHUw2wml6/Gb8+59BsH31KzUr6c1l2BPvqKX8="
google.com.		3599	IN	TXT	"facebook-domain-verification=22rm551cu4k0ab0bxsw536tlds4h95"
google.com.		299	IN	TXT	"docusign=05958488-4752-4ef2-95eb-aa7ba8a3bd0e"
google.com.		299	IN	AAAA	2a00:1450:400c:c00::65
google.com.		21599	IN	CAA	0 issue "pki.goog"

;; Query time: 49 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Tue Mar 10 16:45:11 CET 2020
;; MSG SIZE  rcvd: 649
</code>

Retourne le résultat dans un format court
<code>
$ dig MX google.com +short
10 aspmx.l.google.com.
30 alt2.aspmx.l.google.com.
50 alt4.aspmx.l.google.com.
40 alt3.aspmx.l.google.com.
20 alt1.aspmx.l.google.com.
</code>