【DNS】Host

host 存在與否，有不同的回應

# host {domain}
kali@kali:~$ host www.megacorpone.com
www.megacorpone.com has address 149.56.244.87

kali@kali:~$ host idontexist.megacorpone.com
Host idontexist.megacorpone.com not found: 3(NXDOMAIN)

使用 t 查詢不同type

# host -t {type} {domain}
kali@kali:~$ host -t mx megacorpone.com
megacorpone.com mail is handled by 10 fb.mail.gandi.net.
megacorpone.com mail is handled by 20 spool.mail.gandi.net.
megacorpone.com mail is handled by 50 mail.megacorpone.com.
megacorpone.com mail is handled by 60 mail2.megacorpone.com.

kali@kali:~$ host -t txt megacorpone.com
megacorpone.com descriptive text "Try Harder"
megacorpone.com descriptive text "google-site-verification=U7B_b0HNeBtY4qYGQZNsEYXfCJ32hMNV3GtC0wWq5pA"

自動化查詢

kali@kali:~$ cat list.txt
www
ftp
mail
owa
proxy
router

kali@kali:~$ for ip in $(cat list.txt); do host $ip.megacorpone.com; done
www.megacorpone.com has address 149.56.244.87
Host ftp.megacorpone.com not found: 3(NXDOMAIN)
mail.megacorpone.com has address 51.222.169.212
Host owa.megacorpone.com not found: 3(NXDOMAIN)
Host proxy.megacorpone.com not found: 3(NXDOMAIN)
router.megacorpone.com has address 51.222.169.214

kali@kali:~$ for ip in $(seq 200 254); do host 51.222.169.$ip; done | grep -v "not found"
...
208.169.222.51.in-addr.arpa domain name pointer admin.megacorpone.com.
209.169.222.51.in-addr.arpa domain name pointer beta.megacorpone.com.
210.169.222.51.in-addr.arpa domain name pointer fs1.megacorpone.com.
211.169.222.51.in-addr.arpa domain name pointer intranet.megacorpone.com.
212.169.222.51.in-addr.arpa domain name pointer mail.megacorpone.com.
213.169.222.51.in-addr.arpa domain name pointer mail2.megacorpone.com.
214.169.222.51.in-addr.arpa domain name pointer router.megacorpone.com.
215.169.222.51.in-addr.arpa domain name pointer siem.megacorpone.com.
216.169.222.51.in-addr.arpa domain name pointer snmp.megacorpone.com.
217.169.222.51.in-addr.arpa domain name pointer syslog.megacorpone.com.
218.169.222.51.in-addr.arpa domain name pointer support.megacorpone.com.
219.169.222.51.in-addr.arpa domain name pointer test.megacorpone.com.
220.169.222.51.in-addr.arpa domain name pointer vpn.megacorpone.com.
...