说明：
这是nslookup的man手册，贴出来比较好看
具体：
NSLOOKUP(1) BIND9 NSLOOKUP(1)
NAME
nslookup - query Internet name servers interactively
SYNOPSIS
nslookup [-option] [name | -] [server]
DESCRIPTION
Nslookup is a program to query Internet domain name servers. Nslookup
has two modes: interactive and non-interactive. Interactive mode allows
the user to query name servers for information about various hosts and
domains or to print a list of hosts in a domain. Non-interactive mode
is used to print just the name and requested information for a host or
domain.
ARGUMENTS
Interactive mode is entered in the following cases:
1. when no arguments are given (the default name server will be used)
2. when the first argument is a hyphen (-) and the second argument is
the host name or Internet address of a name server.
Non-interactive mode is used when the name or Internet address of the host to
be looked up is given as the first argument. The optional second argument
specifies the host name or address of a name server.
Options can also be specified on the command line if they precede the
arguments and are prefixed with a hyphen. For example, to change the default
query type to host information, and the initial timeout to 10 seconds, type:
nslookup -query=hinfo -timeout=10
INTERACTIVE COMMANDS
host [server]
Look up information for host using the current default server or
using server, if specified. If host is an Internet address and the
query type is A or PTR, the name of the host is returned. If host
is a name and does not have a trailing period, the search list is
used to qualify the name.
To look up a host not in the current domain, append a period to the
name.
server domain
lserver domain
Change the default server to domain; lserver uses the initial
server to look up information about domain, while server uses the
current default server. If an authoritative answer can’t be found,
the names of servers that might have the answer are returned.
root
not implemented
finger
not implemented
ls
not implemented
view
not implemented
help
not implemented
?
not implemented
exit
Exits the program.
set keyword[=value]
This command is used to change state information that affects the
lookups. Valid keywords are:
all
Prints the current values of the frequently used options to
set. Information about the current default server and host
is also printed.
class=value
Change the query class to one of:
IN
the Internet class
CH
the Chaos class
HS
the Hesiod class
ANY
wildcard
The class specifies the protocol group of the
information.
(Default = IN; abbreviation = cl)
[no]debug
Turn on or off the display of the full response packet and
any intermediate response packets when searching.
(Default = nodebug; abbreviation = [no]deb)
[no]d2
Turn debugging mode on or off. This displays more about
what nslookup is doing.
(Default = nod2)
domain=name
Sets the search list to name.
[no]search
If the lookup request contains at least one period but
doesn’t end with a trailing period, append the domain names
in the domain search list to the request until an answer is
received.
(Default = search)
port=value
Change the default TCP/UDP name server port to value.
(Default = 53; abbreviation = po)
querytype=value
type=value
Change the type of the information query.
(Default = A; abbreviations = q, ty)
[no]recurse
Tell the name server to query other servers if it does not
have the information.
(Default = recurse; abbreviation = [no]rec)
retry=number
Set the number of retries to number.
timeout=number
Change the initial timeout interval for waiting for a reply
to number seconds.
[no]vc
Always use a virtual circuit when sending requests to the
server.
(Default = novc)
[no]fail
Try the next nameserver if a nameserver responds with
SERVFAIL or a referral (nofail) or terminate query (fail)
on such a response.
(Default = nofail)
FILES
/etc/resolv.conf
SEE ALSO
dig(1), host(1), named(8).
AUTHOR
Andrew Cherenson
COPYRIGHT
Copyright © 2004-2007, 2010 Internet Systems Consortium, Inc. ("ISC")
BIND9 Jun 30, 2000 NSLOOKUP(1)