Shulou(Shulou.com)06/02 Report--

[who is nslookup? ]

Nslookup command is a very common network command in Linux. In short, it is "used to check DNS information".

Through man nslookup, you can see that the official interpretation of nslookup is "query Internet name servers interactively".

[who is the author of nslookup? ]

Through man nslookup, we can see that the author is Andrew Cherenson. I found his Linkedin home page.

He is a top student in computer science and has studied at Harvard University and the University of California, Berkeley.

Currently working for ChoiceStream

[the system does not have a nslookup command? ]

If your Linux system does not have the nslookup command, it is likely that you do not have the bind-utils package installed.

Direct yum install bind-utils can solve the problem.

[two modes of nslookup]

Nslookup is a program that can query the information of Internet domain name servers. He has two working modes, namely, "interactive mode" and "non-interactive mode".

In "interactive mode", users can query the information of various hosts and domain names from the domain name server, or output a list of hosts in the domain name.

In "non-interactive mode", users can only get a specific name or required information for a host or domain name.

[how do I enter interactive mode? ]

There are two ways to enter interactive mode.

In the first method, enter the nslookup command directly, without any parameters, and enter interactive mode directly, where nslookup connects to the default domain name server (that is, the first dns address of / etc/resolv.conf).

The second method is to support the selection of different domain name servers. You need to set the first parameter to "-" and then the second parameter to set the hostname or IP address of the domain name server to connect to.

[how do I enter non-interactive mode? ]

If you add the IP or hostname you want to query directly after the nslookup command, you enter non-interactive mode. Of course, you can also set the domain name server you want to connect to in the second parameter location.

1. Nslookup action

Nslookup is used to query the records of DNS, to check whether the domain name resolution is normal, and to diagnose network problems in case of network failure.

2. Query

a. Direct inquiry

Nslookup domain [dns-server] / / if no dns server is specified, the system default dns server is used.

b. Query other records

Nslookup-qt = type domain [dns-server]

Type:

A-- > address record

AAAA-- > address record

AFSDB Andrew-- > File system database server records

ATMA-- > ATM address record

CNAME-- > alias record

HINHO-- > hardware configuration record, including CPU and operating system information

ISDN-- > the ISDN number corresponding to the domain name

MB-- > the server where the specified mailbox is stored

MG-- > Mail group record

MINFO-- > Information records for mail groups and mailboxes

MR-- > mailbox records with renamed names

MX-- > Mail server record

NS-- > name server record

PTR-> reverse recording

RP-- > responsible person's record

RT-- > routing traversal record

SRV-- > TCP server information record

TXT-- > text message for domain name

X25-- > X.25 address record for domain name

c. Query for more specific information

Nslookup-d [other parameters] domain [dns-server] / / as long as you add the-d parameter when querying, you can query the domain name cache.

Example

[root@localhost ~] # nslookup www.jsdig.comServer: 202.96.104.15Address: 202.96.104.15#53Non-authoritative answer:www.jsdig.com canonical name = host.1.jsdig.com.Name: host.1.jsdig.comAddress: 100.42.212.8

The above is the whole content of this article, I hope it will be helpful to your study, and I also hope that you will support it.

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