NAME(名稱)

dig - 發(fā)送域名查詢信息包到域名服務(wù)器  

SYNOPSIS(總覽)

dig [@ server ] domain [Aq query-type ] [Aq query-class ] [+ Aq query-option ] [-Aq dig-option ] [%comment ]  

DESCRIPTION(描述)

Dig (domain information groper 域名信息搜索)是一個靈活的命令行工具, 它可以用來從域名系統(tǒng)服務(wù)器中收集信息. Dig 有兩種模式:簡單交互模式用于簡單的查詢,而批處理模式則可以對包含多個查詢條目的列表執(zhí)行查詢. 所有查詢選項都可以從命令行輸入.

通常簡單的 dig 用法為下列格式:

dig @ server domain query-type query-class

這里:

server

可為域名或者以點分隔的Internet地址. 如果省略該可選字段, dig 會嘗試使用你機器的默認域名服務(wù)器.

注意: 如果指定了一個域名,那么將使用域名系統(tǒng)解析程序 (即BIND)來進行解析. 如果你的系統(tǒng)不支持DNS,那么可能 必須 指定一個以點分隔的地址.另外一種選擇是, 如果在你配置的某個地方有一臺這樣的服務(wù)器, 那么你所要做的就是建立 /etc/resolv.conf 并在其中指明默認域名服務(wù)器的位置,這樣 server 自身就可以解析了.參看 resolver(5) 以獲得 /etc/resolv.conf 相關(guān)的信息. 警告: 修改 /etc/resolv.conf 同樣會對標準的解析程序庫產(chǎn)生影響,而 (潛在地) 某些程序會要用到它. 作為一種選擇,用戶可設(shè)置環(huán)境變量 LOCALRES 為指定的文件,這將用來取代 /etc/resolv.conf Po Ns Ev LOCALRES 是特定針對 dig 解析程序的,并不會牽涉到標準解析程序 Pc . 如果 LOCALRES 變量未設(shè)置或者指定的文件不能讀,那么就使用 /etc/resolf.conf .

domain

是指一個你請求信息的域名. 參看 -x 選項(在該部分的 Sx OTHER OPTIONS 節(jié)中有介紹)以獲知指定反向地址查詢的便捷方法.

query-type

是指你所請求的信息類型(DNS查詢類型). 如果省略,默認為 ``a '' (T_A = address . ) 以下類型是可識別的:

a       T_A

網(wǎng)絡(luò)地址

any     T_ANY

所有/任何與指定域相關(guān)的信息

mx      T_MX

該域的郵件網(wǎng)關(guān)

ns      T_NS

域名服務(wù)器

soa     T_SOA

區(qū)域的授權(quán)記錄

hinfo   T_HINFO

主機信息

axfr    T_AXFR

區(qū)域傳輸記錄(必須是詢問一臺授權(quán)的服務(wù)器)

txt     T_TXT

任意的字符串信息

(參看RFC 1035以獲得完整的列表.)

query-class

是指在查詢中請求的網(wǎng)絡(luò)等級.如果省略,默認為 ``in '' (C_IN = Internet . ) 以下的等級是可識別的:

in      C_IN

Internet等級的域

any     C_ANY

所有/任何等級的信息

(參看RFC 1035以獲得完整的列表.)

注意: ``Any '' 可以用來指定一個 等級 和/或查詢的一種 類型 . Dig 會將第一次出現(xiàn)的 ``any '' 解釋為 query-type = T_ANY . 為了指明 query-class = C_ANY , 你必須或者指定 ``any'' 兩次,或者使用 -c 選項(見下面)設(shè)置 query-class .

OTHER OPTIONS(其它選項)

% ignored-comment

``%'' 用來引用一個不用作解釋的參數(shù). 如果正以批處理的模式運行 dig 這可能很有用. 因為不用對一組查詢中的每個 @server-domain-name 進行解析,你就可以避免這樣做的額外開銷, 并且仍然能夠在命令行上以域名作為參數(shù). 例如:

dig @128.9.0.32 %venera.isi.edu mx isi.edu

-Aq dig option

``- '' 用來指定一個影響 dig 操作的選項. 當前可用的選項有(盡管不能保證都有用):

-x dot-notation-address

這是指定反向地址映射的便捷的方法. 不用寫 ``dig 32.0.9.128.in-addr.arpa , '' 你可以簡單地寫成 ``dig -x 128.9.0.32 . ''

-f file

dig 批處理模式的文件.該文件包含了一組查詢清單 ( dig 命令行),它們將一個接一個地執(zhí)行.以 `; ，' `#' 或 `\n' 開頭的行將忽略.其它選項仍然可以在命令行上出現(xiàn),而且對每個批處理查詢都有效.

-T time

當運行于批處理模式下時,兩次接著的查詢之間的時間間隔,以秒計. 可以用來保持兩個或多個批處理 dig 命令大致同步運行.默認為零.

-p port

端口號.通過監(jiān)聽非標準端口號來查詢域名服務(wù)器.默認為53.

-P Bq ping-string

在查詢返回之后,執(zhí)行一次 ping(8) 命令以獲得響應(yīng)時間的對照關(guān)系.這在調(diào)用shell上顯得不那么自然. 該命令顯示的最后三行統(tǒng)計信息為:

ping -s server_name 56 3

如果可選的 ``ping_string '' 存在,那么會覆蓋shell命令中的 ``ping -s . ''

-t query-type

指定查詢類型.可以指定為一個將包含在類型字段中的整數(shù)值,也可以使用上面討論的縮寫助記符(即 mx = T_MX ) .

-c query-class

指定查詢等級.可以指定為一個將包含在等級字段中的整數(shù)值,也可以使用上面討論的縮寫助記符(即in = C_IN).

-k keydir:keyname

用TSIG密鑰指定的的密鑰名來簽署這次查詢, 該密鑰名在目錄keydir下.

-envsav

該標識指定 dig 的環(huán)境變量 (默認的,顯示選項,等等.),在所有參數(shù)都解釋了之后, 應(yīng)保存它們到一個文件中以使之成為默認的環(huán)境變量. 如果你不喜歡默認的標準設(shè)置而又不想在每次使用 dig 時帶大量的選項,那么這很有用. 環(huán)境變量包括解析程序狀態(tài)變量標識,超時和重試次數(shù)以及詳細控制 dig 輸出的標識(見下面). 如果shell環(huán)境變量 LOCALDEF 設(shè)置為一個文件的名字,那么此即為默認的 dig 環(huán)境變量所保存的地方.如果沒有,那么會在當前工作目錄下創(chuàng)建 ``DiG.env . ''

注意: LOCALDEF 是特定針對 dig 解析程序, 而它不會影響標準解析程序庫的操作.

每當 dig 執(zhí)行時,它會查找 ``./DiG.env '' 或者在shell環(huán)境變量 LOCALDEF 中指定的文件. 如果這樣的文件存在而且可讀,那么在解釋任何參數(shù)之前, 先從該文件中恢復(fù)環(huán)境變量.

-envset

該標識只影響批處理查詢的運行.當在 dig 的批處理文件一行上指定了 ``-envset '' 時,在參數(shù)之后的 dig 環(huán)境變量會被解釋為批處理文件執(zhí)行期間默認的環(huán)境變量, 或者直到指定了 ``-envset '' 的下一行為止.

-[no ] cm stick

該標識只影響批處理查詢的運行. 它指定 dig 環(huán)境變量(通過 ``-envset '' 開關(guān)變量初始化讀入或設(shè)置)會在 dig 批處理文件每次查詢(行)之前重建. 默認的 ``-nostick '' 表示 dig 環(huán)境變量不是固定的,因而在 dig 批處理文件中單行上指定的選項將對剩余的行繼續(xù)產(chǎn)生作用(也即,它們不會恢復(fù)成 ``sticky(固定的)'' 默認值).

+ Aq query-option

``+'' 用來指定一個在查詢信息包中需修改的或者需用來修改 dig 輸出細節(jié)的選項.這些選項中的許多與 nslookup(8) 所承認的參數(shù)相同. 如果一個選項需帶參數(shù),那么格式如下:

+ keyword [= value ]

絕大多數(shù)關(guān)鍵字可簡寫. ``+'' 選項的解釋是非常直白的 --- 值與它的關(guān)鍵字之間千萬不能用空格分隔. 當前可用的關(guān)鍵字有:

Keyword Abbrev. Meaning [default]

(關(guān)鍵字) (縮寫) (含義) [默認值]

[no ] debug     (deb )

打開/關(guān)閉調(diào)試模式 Bq Cm deb

[no ] d2          

打開/關(guān)閉特殊的調(diào)試模式 Bq Cm nod2

[no ] recurse   (rec )

使用/不使用遞歸查詢 Bq Cm rec

retry= #       (ret )

設(shè)置重試次數(shù)為# Bq 4

time= #        (ti )

設(shè)置超時長度為#秒 Bq 4

[no ] ko

保留公開的選項(keep open options)(隱含vc) Bq Cm noko

[no ] vc

使用/不使用虛擬電路 Bq Cm novc

[no ] defname   (def )

使用/不使用默認的域名 Bq Cm def

[no ] search    (sea )

使用/不使用域搜索列表 Bq Cm sea

domain= NAME   (do )

設(shè)置默認的域名為 NAME

[no ] ignore    (i )

忽略/不忽略截斷(trunc.)錯誤 Bq Cm noi

[no ] primary   (pr )

使用/不使用主服務(wù)器 Bq Cm nopr

[no ] aaonly    (aa )

表示只包含授權(quán)查詢的標識 Bq Cm noaa

[no ] cmd

重復(fù)(echo)解釋的參數(shù) Bq Cm cmd

[no ] stats     (st )

顯示查詢統(tǒng)計信息 Bq Cm st

[no ] Header    (H )

顯示基本的包頭 Bq Cm H

[no ] header    (he )

顯示包頭的標識 Bq Cm he

[no ] ttlid     (tt )

顯示TTLs(Time to Live) Bq Cm tt

[no ] cl

顯示等級信息 Bq Cm nocl

[no ] qr

顯示向外的查詢 Bq Cm noqr

[no ] reply     (rep )

顯示響應(yīng)信息 Bq Cm rep

[no ] ques      (qu )

顯示詢問部分 Bq Cm qu

[no ] answer    (an )

顯示應(yīng)答部分 Bq Cm an

[no ] author    (au )

顯示授權(quán)的部分 Bq Cm au

[no ] addit     (ad )

顯示附加的部分 Bq Cm ad

pfdef

設(shè)置為默認顯示位

pfmin

設(shè)置為最小的默認顯示位

pfset= #

設(shè)置顯示位為# (#可以為十六進制/八進制/十進制)

pfand= #

位和顯示位設(shè)為#(bitwise and print flags with #)

pfor= #

位或顯示位設(shè)為#(bitwise or print flags with #)

當發(fā)送數(shù)據(jù)報查詢時, retry 和 time 選項會影響解析程序庫的重傳策略.其算法如下:

for i = 0 to retry - 1
    for j = 1 to num_servers
        send_query
        wait((time * (2**i)) / num_servers)
    end
end

(注意: dig 通常取 ``num_servers '' 的值為1 . )

DETAILS(細節(jié))

Dig 以前要求BIND的 resolver(3) 庫的版本作一些細微的修改. 從BIND 4.9起,BIND的解析程序已經(jīng)修補好并可以正常地與 dig 一起工作. 實質(zhì)上, dig 在解釋參數(shù)和設(shè)置適合的參數(shù)時是直來直去的 (雖然并不巧妙) Dig 會用到 resolver(3) 的例程 Fn res_init , Fn res_mkquery , Fn res_send 以及訪問 Ft _res 結(jié)構(gòu).  

ENVIRONMENT(環(huán)境變量)

LOCALRES

用來替換Pa /etc/resolv.conf的文件

LOCALDEF

默認的環(huán)境變量文件

另見上面對 -envsav , -envset , 和 -[no ] stick 選項的說明.  

FILES(相關(guān)文件)

/etc/resolv.conf       

初始化的域名和域名服務(wù)器地址

./DiG.env

默認的保存默認選項的文件

SEE ALSO(另見)

named(8), resolver(3), resolver(5), nslookup(8).  

#p#

NAME

dig - DNS lookup utility  

SYNOPSIS

dig [ @server ] [ -b address ] [ -c class ] [ -f filename ] [ -k filename ] [ -p port# ] [ -t type ] [ -x addr ] [ -y name:key ] [ name ] [ type ] [ class ] [ queryopt... ]

dig [ -h ]

dig [ global-queryopt... ] [ query... ]  

DESCRIPTION

dig (domain information groper) is a flexible tool for interrogating DNS name servers. It performs DNS lookups and displays the answers that are returned from the name server(s) that were queried. Most DNS administrators use dig to troubleshoot DNS problems because of its flexibility, ease of use and clarity of output. Other lookup tools tend to have less functionality than dig.

Although dig is normally used with command-line arguments, it also has a batch mode of operation for reading lookup requests from a file. A brief summary of its command-line arguments and options is printed when the -h option is given. Unlike earlier versions, the BIND9 implementation of dig allows multiple lookups to be issued from the command line.

Unless it is told to query a specific name server, dig will try each of the servers listed in /etc/resolv.conf.

When no command line arguments or options are given, will perform an NS query for "." (the root).

It is possible to set per user defaults for dig via ${HOME}/.digrc. This file is read and any options in it are applied before the command line arguments.  

SIMPLE USAGE

A typical invocation of dig looks like:

 dig @server name type 

where:

server

is the name or IP address of the name server to query. This can be an IPv4 address in dotted-decimal notation or an IPv6 address in colon-delimited notation. When the supplied server argument is a hostname, dig resolves that name before querying that name server. If no server argument is provided, dig consults /etc/resolv.conf and queries the name servers listed there. The reply from the name server that responds is displayed.

name

is the name of the resource record that is to be looked up.

type

indicates what type of query is required --- ANY, A, MX, SIG, etc. type can be any valid query type. If no type argument is supplied, dig will perform a lookup for an A record.

OPTIONS

The -b option sets the source IP address of the query to address. This must be a valid address on one of the host's network interfaces.

The default query class (IN for internet) is overridden by the -c option. class is any valid class, such as HS for Hesiod records or CH for CHAOSNET records.

The -f option makes dig operate in batch mode by reading a list of lookup requests to process from the file filename. The file contains a number of queries, one per line. Each entry in the file should be organised in the same way they would be presented as queries to dig using the command-line interface.

If a non-standard port number is to be queried, the -p option is used. port# is the port number that dig will send its queries instead of the standard DNS port number 53. This option would be used to test a name server that has been configured to listen for queries on a non-standard port number.

The -t option sets the query type to type. It can be any valid query type which is supported in BIND9. The default query type "A", unless the -x option is supplied to indicate a reverse lookup. A zone transfer can be requested by specifying a type of AXFR. When an incremental zone transfer (IXFR) is required, type is set to ixfr=N. The incremental zone transfer will contain the changes made to the zone since the serial number in the zone's SOA record was N.

Reverse lookups - mapping addresses to names - are simplified by the -x option. addr is an IPv4 address in dotted-decimal notation, or a colon-delimited IPv6 address. When this option is used, there is no need to provide the name, class and type arguments. dig automatically performs a lookup for a name like 11.12.13.10.in-addr.arpa and sets the query type and class to PTR and IN respectively. By default, IPv6 addresses are looked up using the IP6.ARPA domain and binary labels as defined in RFC2874. To use the older RFC1886 method using the IP6.INT domain and "nibble" labels, specify the -n (nibble) option.

To sign the DNS queries sent by dig and their responses using transaction signatures (TSIG), specify a TSIG key file using the -k option. You can also specify the TSIG key itself on the command line using the -y option; name is the name of the TSIG key and key is the actual key. The key is a base-64 encoded string, typically generated by dnssec-keygen(8). Caution should be taken when using the -y option on multi-user systems as the key can be visible in the output from ps(1) or in the shell's history file. When using TSIG authentication with dig, the name server that is queried needs to know the key and algorithm that is being used. In BIND, this is done by providing appropriate key and server statements in named.conf.  

QUERY OPTIONS

dig provides a number of query options which affect the way in which lookups are made and the results displayed. Some of these set or reset flag bits in the query header, some determine which sections of the answer get printed, and others determine the timeout and retry strategies.

Each query option is identified by a keyword preceded by a plus sign (+). Some keywords set or reset an option. These may be preceded by the string no to negate the meaning of that keyword. Other keywords assign values to options like the timeout interval. They have the form +keyword=value. The query options are:

+[no]tcp

Use [do not use] TCP when querying name servers. The default behaviour is to use UDP unless an AXFR or IXFR query is requested, in which case a TCP connection is used.

+[no]vc

Use [do not use] TCP when querying name servers. This alternate syntax to +[no]tcp is provided for backwards compatibility. The "vc" stands for "virtual circuit".

+[no]ignore

Ignore truncation in UDP responses instead of retrying with TCP. By default, TCP retries are performed.

+domain=somename

Set the search list to contain the single domain somename, as if specified in a domain directive in /etc/resolv.conf, and enable search list processing as if the +search option were given.

+[no]search

Use [do not use] the search list defined by the searchlist or domain directive in resolv.conf (if any). The search list is not used by default.

+[no]defname

Deprecated, treated as a synonym for +[no]search

+[no]aaonly

This option does nothing. It is provided for compatibility with old versions of dig where it set an unimplemented resolver flag.

+[no]adflag

Set [do not set] the AD (authentic data) bit in the query. The AD bit currently has a standard meaning only in responses, not in queries, but the ability to set the bit in the query is provided for completeness.

+[no]cdflag

Set [do not set] the CD (checking disabled) bit in the query. This requests the server to not perform DNSSEC validation of responses.

+[no]recurse

Toggle the setting of the RD (recursion desired) bit in the query. This bit is set by default, which means dig normally sends recursive queries. Recursion is automatically disabled when the +nssearch or +trace query options are used.

+[no]nssearch

When this option is set, dig attempts to find the authoritative name servers for the zone containing the name being looked up and display the SOA record that each name server has for the zone.

+[no]trace

Toggle tracing of the delegation path from the root name servers for the name being looked up. Tracing is disabled by default. When tracing is enabled, dig makes iterative queries to resolve the name being looked up. It will follow referrals from the root servers, showing the answer from each server that was used to resolve the lookup.

+[no]cmd

toggles the printing of the initial comment in the output identifying the version of dig and the query options that have been applied. This comment is printed by default.

+[no]short

Provide a terse answer. The default is to print the answer in a verbose form.

+[no]identify

Show [or do not show] the IP address and port number that supplied the answer when the +short option is enabled. If short form answers are requested, the default is not to show the source address and port number of the server that provided the answer.

+[no]comments

Toggle the display of comment lines in the output. The default is to print comments.

+[no]stats

This query option toggles the printing of statistics: when the query was made, the size of the reply and so on. The default behaviour is to print the query statistics.

+[no]qr

Print [do not print] the query as it is sent. By default, the query is not printed.

+[no]question

Print [do not print] the question section of a query when an answer is returned. The default is to print the question section as a comment.

+[no]answer

Display [do not display] the answer section of a reply. The default is to display it.

+[no]authority

Display [do not display] the authority section of a reply. The default is to display it.

+[no]additional

Display [do not display] the additional section of a reply. The default is to display it.

+[no]all

Set or clear all display flags.

+time=T

Sets the timeout for a query to T seconds. The default time out is 5 seconds. An attempt to set T to less than 1 will result in a query timeout of 1 second being applied.

+tries=T

Sets the number of times to retry UDP queries to server to T instead of the default, 3. If T is less than or equal to zero, the number of retries is silently rounded up to 1.

+ndots=D

Set the number of dots that have to appear in name to D for it to be considered absolute. The default value is that defined using the ndots statement in /etc/resolv.conf, or 1 if no ndots statement is present. Names with fewer dots are interpreted as relative names and will be searched for in the domains listed in the search or domain directive in /etc/resolv.conf.

+bufsize=B

Set the UDP message buffer size advertised using EDNS0 to B bytes. The maximum and minimum sizes of this buffer are 65535 and 0 respectively. Values outside this range are rounded up or down appropriately.

+[no]multiline

Print records like the SOA records in a verbose multi-line format with human-readable comments. The default is to print each record on a single line, to facilitate machine parsing of the dig output.

+[no]fail

Do not try the next server if you receive a SERVFAIL. The default is to not try the next server which is the reverse of normal stub resolver behaviour.

+[no]besteffort

Attempt to display the contents of messages which are malformed. The default is to not display malformed answers.

+[no]dnssec

Requests DNSSEC records be sent by setting the DNSSEC OK bit (DO) in the OPT record in the additional section of the query.

MULTIPLE QUERIES

The BIND 9 implementation of dig supports specifying multiple queries on the command line (in addition to supporting the -f batch file option). Each of those queries can be supplied with its own set of flags, options and query options.

In this case, each query argument represent an individual query in the command-line syntax described above. Each consists of any of the standard options and flags, the name to be looked up, an optional query type and class and any query options that should be applied to that query.

A global set of query options, which should be applied to all queries, can also be supplied. These global query options must precede the first tuple of name, class, type, options, flags, and query options supplied on the command line. Any global query options (except the +[no]cmd option) can be overridden by a query-specific set of query options. For example:

dig +qr www.isc.org any -x 127.0.0.1 isc.org ns +noqr

shows how dig could be used from the command line to make three lookups: an ANY query for www.isc.org, a reverse lookup of 127.0.0.1 and a query for the NS records of isc.org. A global query option of +qr is applied, so that dig shows the initial query it made for each lookup. The final query has a local query option of +noqr which means that dig will not print the initial query when it looks up the NS records for isc.org.  

FILES

/etc/resolv.conf

${HOME}/.digrc  

SEE ALSO

host(1), named(8), dnssec-keygen(8), RFC1035.