diff options
Diffstat (limited to 'misc/slackbook/html/basic-network-commands-dns.html')
| -rw-r--r-- | misc/slackbook/html/basic-network-commands-dns.html | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/misc/slackbook/html/basic-network-commands-dns.html b/misc/slackbook/html/basic-network-commands-dns.html new file mode 100644 index 00000000..f8881aad --- /dev/null +++ b/misc/slackbook/html/basic-network-commands-dns.html @@ -0,0 +1,181 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml"> +<head> +<meta name="generator" content="HTML Tidy, see www.w3.org" /> +<title>DNS Tools</title> +<meta name="GENERATOR" content="Modular DocBook HTML Stylesheet Version 1.7" /> +<link rel="HOME" title="Slackware Linux Essentials" href="index.html" /> +<link rel="UP" title="Basic Network Commands" href="basic-network-commands.html" /> +<link rel="PREVIOUS" title="traceroute" href="basic-network-commands-traceroute.html" /> +<link rel="NEXT" title="finger" href="basic-network-commands-finger.html" /> +<link rel="STYLESHEET" type="text/css" href="docbook.css" /> +<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> +</head> +<body class="SECT1" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#840084" +alink="#0000FF"> +<div class="NAVHEADER"> +<table summary="Header navigation table" width="100%" border="0" cellpadding="0" +cellspacing="0"> +<tr> +<th colspan="3" align="center">Slackware Linux Essentials</th> +</tr> + +<tr> +<td width="10%" align="left" valign="bottom"><a +href="basic-network-commands-traceroute.html" accesskey="P">Prev</a></td> +<td width="80%" align="center" valign="bottom">Chapter 13 Basic Network Commands</td> +<td width="10%" align="right" valign="bottom"><a +href="basic-network-commands-finger.html" accesskey="N">Next</a></td> +</tr> +</table> + +<hr align="LEFT" width="100%" /> +</div> + +<div class="SECT1"> +<h1 class="SECT1"><a id="BASIC-NETWORK-COMMANDS-DNS" +name="BASIC-NETWORK-COMMANDS-DNS">13.3 DNS Tools</a></h1> + +<p>Domain Name Service (DNS for short) is that magical protocol that allows your computer +to turn meaningless domain names like www.slackware.com into meaningful IP address like +<tt class="HOSTID">64.57.102.34</tt>. Computers can't route packets to www.slackware.com, +but they can route packets to that domain name's IP address. This gives us a convenient +way to remember machines. Without DNS we'd have to keep a mental database of just what IP +address belongs to what computer, and that's assuming the IP address doesn't change. +Clearly using names for computers is better, but how do we map names to IP addresses?</p> + +<div class="SECT2"> +<h2 class="SECT2"><a id="AEN4475" name="AEN4475">13.3.1 <tt +class="COMMAND">host</tt></a></h2> + +<p><tt class="COMMAND">host</tt>(1) can do this for us. <tt class="COMMAND">host</tt> is +used to map names to IP addresses. It is a very quick and simple utility without a lot of +functions.</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">host www.slackware.com</kbd> +www.slackware.com is an alias for slackware.com. +slackware.com has address 64.57.102.34 +</pre> +</td> +</tr> +</table> + +<p>But let's say for some reason we want to map an IP address to a domain name; what +then?</p> +</div> + +<div class="SECT2"> +<h2 class="SECT2"><a id="AEN4487" name="AEN4487">13.3.2 <tt +class="COMMAND">nslookup</tt></a></h2> + +<p><tt class="COMMAND">nslookup</tt> is a tried and true program that has weathered the +ages. <tt class="COMMAND">nslookup</tt> has been deprecated and may be removed from +future releases. There is not even a man page for this program.</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">nslookup 64.57.102.34</kbd> +Note: nslookup is deprecated and may be removed from future releases. +Consider using the `dig' or `host' programs instead. Run nslookup with +the `-sil[ent]' option to prevent this message from appearing. +Server: 192.168.1.254 +Address: 192.168.1.254#53 + +Non-authoritative answer: +www.slackware.com canonical name = slackware.com. +Name: slackware.com +Address: 64.57.102.34 +</pre> +</td> +</tr> +</table> +</div> + +<div class="SECT2"> +<h2 class="SECT2"><a id="AEN4496" name="AEN4496">13.3.3 <tt +class="COMMAND">dig</tt></a></h2> + +<p>The meanest dog in the pound, the domain information groper, <tt +class="COMMAND">dig</tt>(1) for short, is the go-to program for finding DNS information. +<tt class="COMMAND">dig</tt> can grab just about anything from a DNS server including +reverse lookups, A, CNAME, MX, SP, and TXT records. <tt class="COMMAND">dig</tt> has many +command line options and if you're not familiar with it you should read through it's +extensive man page.</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">%</samp> <kbd +class="USERINPUT">dig @192.168.1.254 www.slackware.com mx</kbd> + +; <<>> DiG 9.2.2 <<>> @192.168.1.254 www.slackware.com mx +;; global options: printcmd +;; Got answer: +;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 26362 +;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 2 + +;; QUESTION SECTION: +;www.slackware.com. IN MX + +;; ANSWER SECTION: +www.slackware.com. 76634 IN CNAME slackware.com. +slackware.com. 86400 IN MX 1 mail.slackware.com. + +;; AUTHORITY SECTION: +slackware.com. 86400 IN NS ns1.cwo.com. +slackware.com. 86400 IN NS ns2.cwo.com. + +;; ADDITIONAL SECTION: +ns1.cwo.com. 163033 IN A 64.57.100.2 +ns2.cwo.com. 163033 IN A 64.57.100.3 + +;; Query time: 149 msec +;; SERVER: 192.168.1.254#53(192.168.1.254) +;; WHEN: Sat Nov 6 16:59:31 2004 +;; MSG SIZE rcvd: 159 +</pre> +</td> +</tr> +</table> + +<p>This should give you an idea how <tt class="COMMAND">dig</tt> works. +“@192.168.1.254” specifies the dns server to use. +“www.slackware.com” is the domain name I am performing a lookup on, and +“mx” is the type of lookup I am performing. The above query tells me that +e-mail to <tt class="HOSTID">www.slackware.com</tt> will instead be sent to <tt +class="HOSTID">mail.slackware.com</tt> for delivery.</p> +</div> +</div> + +<div class="NAVFOOTER"> +<hr align="LEFT" width="100%" /> +<table summary="Footer navigation table" width="100%" border="0" cellpadding="0" +cellspacing="0"> +<tr> +<td width="33%" align="left" valign="top"><a +href="basic-network-commands-traceroute.html" accesskey="P">Prev</a></td> +<td width="34%" align="center" valign="top"><a href="index.html" +accesskey="H">Home</a></td> +<td width="33%" align="right" valign="top"><a href="basic-network-commands-finger.html" +accesskey="N">Next</a></td> +</tr> + +<tr> +<td width="33%" align="left" valign="top"><tt class="COMMAND">traceroute</tt></td> +<td width="34%" align="center" valign="top"><a href="basic-network-commands.html" +accesskey="U">Up</a></td> +<td width="33%" align="right" valign="top"><tt class="COMMAND">finger</tt></td> +</tr> +</table> +</div> +</body> +</html> + |