163 lines
6.2 KiB
HTML
163 lines
6.2 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
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<!--Converted with LaTeX2HTML 96.1-c (Feb 29, 1996) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds -->
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<HTML>
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<HEAD>
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<TITLE>Verifying the Name Server Setup</TITLE>
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</HEAD>
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<BODY LANG="EN">
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<A HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif"></A> <BR>
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<B> Next:</B> <A HREF="node91.html">Other Useful Tools</A>
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<B>Up:</B> <A HREF="node86.html">Running named</A>
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<B> Previous:</B> <A HREF="node89.html">Writing the Master Files</A>
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<BR> <P>
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<H2><A NAME="SECTION008240000">Verifying the Name Server Setup</A></H2>
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<A NAME="resolvnslookup"></A>
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<A NAME="3619"></A>
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<A NAME="3620"></A>
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<A NAME="3702"></A>
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<A NAME="3622"></A>
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<A NAME="3623"></A>
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<A NAME="3624"></A>
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There's a fine tool for checking the operation of your name server
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setup. It is called nslookup, and may be used both interactively
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and from the command line. In the latter case, you simply invoke it
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as
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<pre>
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nslookup hostname
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</pre>
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and it will query the name server specified in resolv.conf for
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hostname. (If this file names more than one server,
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nslookup will choose one at random).
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<P>
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The interactive mode, however, is much more exciting. Besides looking
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up individual hosts, you may query for any type of DNS record, and
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transfer the entire zone information for a domain.
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<P>
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When invoked without argument, nslookup will display the name
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server it uses, and enter interactive mode. At the `>' prompt,
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you may type any domain name it should query for. By default, it asks
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for class A records, those containing the IP-address relating to the
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domain name.
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<P>
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You may change this type by issuing ``set type=<I>type</I>'', where
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type is one of the resource record names described above in
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section-<A HREF="node86.html#resolvnamed"><IMG ALIGN=BOTTOM ALT="gif" SRC="cross_ref_motif.gif"></A>, or ANY.
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<P>
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For example, you might have the following dialogue with it:
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<pre>
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$ nslookup
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Default Name Server: rs10.hrz.th-darmstadt.de
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Address: 130.83.56.60
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> sunsite.unc.edu
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Name Server: rs10.hrz.th-darmstadt.de
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Address: 130.83.56.60
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Non-authoritative answer:
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Name: sunsite.unc.edu
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Address: 152.2.22.81
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</pre>
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If you try to query for a name that has no IP-address associated, but
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other records were found in the DNS database, nslookup will come
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back with an error message saying ``No type A records found''.
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However, you can make it query for records other than type A by issuing
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the ``set type'' command. For example, to get the SOA record of
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unc.edu, you would issue:
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<pre>
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> unc.edu
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*** No address (A) records available for unc.edu
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Name Server: rs10.hrz.th-darmstadt.de
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Address: 130.83.56.60
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> set type=SOA
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> unc.edu
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Name Server: rs10.hrz.th-darmstadt.de
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Address: 130.83.56.60
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Non-authoritative answer:
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unc.edu
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origin = ns.unc.edu
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mail addr = shava.ns.unc.edu
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serial = 930408
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refresh = 28800 (8 hours)
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retry = 3600 (1 hour)
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expire = 1209600 (14 days)
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minimum ttl = 86400 (1 day)
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Authoritative answers can be found from:
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UNC.EDU nameserver = SAMBA.ACS.UNC.EDU
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SAMBA.ACS.UNC.EDU internet address = 128.109.157.30
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</pre>
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In a similar fashion you can query for MX records, etc. Using a type of
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ANY returns all resource records associated with a given name.
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<pre>
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> set type=MX
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> unc.edu
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Non-authoritative answer:
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unc.edu preference = 10, mail exchanger = lambada.oit.unc.edu
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lambada.oit.unc.edu internet address = 152.2.22.80
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Authoritative answers can be found from:
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UNC.EDU nameserver = SAMBA.ACS.UNC.EDU
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SAMBA.ACS.UNC.EDU internet address = 128.109.157.30
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</pre>
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<A NAME="3647"></A>
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<A NAME="3648"></A>
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A practical application of nslookup beside debugging is
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to obtain the current list of root name servers for the named.ca
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file. You can do this by querying for all type NS records associated
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with the root domain:
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<pre>
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> set typ=NS
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> .
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Name Server: fb0430.mathematik.th-darmstadt.de
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Address: 130.83.2.30
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Non-authoritative answer:
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(root) nameserver = NS.INTERNIC.NET
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(root) nameserver = AOS.ARL.ARMY.MIL
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(root) nameserver = C.NYSER.NET
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(root) nameserver = TERP.UMD.EDU
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(root) nameserver = NS.NASA.GOV
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(root) nameserver = NIC.NORDU.NET
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(root) nameserver = NS.NIC.DDN.MIL
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Authoritative answers can be found from:
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(root) nameserver = NS.INTERNIC.NET
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(root) nameserver = AOS.ARL.ARMY.MIL
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(root) nameserver = C.NYSER.NET
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(root) nameserver = TERP.UMD.EDU
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(root) nameserver = NS.NASA.GOV
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(root) nameserver = NIC.NORDU.NET
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(root) nameserver = NS.NIC.DDN.MIL
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NS.INTERNIC.NET internet address = 198.41.0.4
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AOS.ARL.ARMY.MIL internet address = 128.63.4.82
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AOS.ARL.ARMY.MIL internet address = 192.5.25.82
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AOS.ARL.ARMY.MIL internet address = 26.3.0.29
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C.NYSER.NET internet address = 192.33.4.12
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TERP.UMD.EDU internet address = 128.8.10.90
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NS.NASA.GOV internet address = 128.102.16.10
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NS.NASA.GOV internet address = 192.52.195.10
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NS.NASA.GOV internet address = 45.13.10.121
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NIC.NORDU.NET internet address = 192.36.148.17
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NS.NIC.DDN.MIL internet address = 192.112.36.4
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</pre>
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The complete set of commands available with nslookup may be
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obtained by the help command from within nslookup.
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<P>
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<A NAME="3703"></A>
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<P>
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<HR><A HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif"></A> <BR>
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<B> Next:</B> <A HREF="node91.html">Other Useful Tools</A>
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<B>Up:</B> <A HREF="node86.html">Running named</A>
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<B> Previous:</B> <A HREF="node89.html">Writing the Master Files</A>
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<P><ADDRESS>
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<I>Andrew Anderson <BR>
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Thu Mar 7 23:22:06 EST 1996</I>
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</ADDRESS>
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</BODY>
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</HTML>
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