defaria.com/blogs/General/archives/2010/03/broken-dns.html

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
   2     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
   3 <html xmlns="http://www.w3.org/1999/xhtml" id="sixapart-standard">
   4 <head>
   5     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
   6 <meta name="generator" content="Movable Type 5.2.3" />
   7 <link rel="stylesheet" href="http://defaria.com/blogs/General/styles.css" type="text/css" />
   8 <link rel="start" href="http://defaria.com/blogs/General/" title="Home" />
   9 <link rel="alternate" type="application/atom+xml" title="Recent Entries" href="http://defaria.com/blogs/General/atom.xml" />
  10 <script type="text/javascript" src="http://defaria.com/blogs/General/mt.js"></script>
  11
  12
  13
  14     <link rel="prev bookmark" href="http://defaria.com/blogs/General/archives/2010/02/making-it-way-h.html" title="Making it way harder than it needs to be" />
  15     <link rel="next bookmark" href="http://defaria.com/blogs/General/archives/2010/03/priority-queues.html" title="Priority Queues..." />
  16
  17
  18     <title>Broken DNS - General</title>
  19 </head>
  20 <body id="classic-blog" class="mt-entry-archive layout-wtt">
  21     <div id="container">
  22         <div id="container-inner">
  23
  24
  25             <div id="header">
  26     <div id="header-inner">
  27         <div id="header-content">
  28
  29
  30             <div id="header-name"><a href="http://defaria.com/blogs/General/" accesskey="1">General</a></div>
  31             <div id="header-description"></div>
  32
  33         </div>
  34     </div>
  35 </div>
  36
  37
  38
  39             <div id="content">
  40                 <div id="content-inner">
  41
  42
  43                     <div id="alpha">
  44                         <div id="alpha-inner">
  45
  46
  47                             <div id="entry-722" class="entry-asset asset hentry">
  48                                 <div class="asset-header">
  49                                     <h1 id="page-title" class="asset-name entry-title">Broken DNS</h1>
  50                                     <div class="asset-meta">
  51                                         <span class="byline">
  52
  53                                             <abbr class="published" title="2010-03-01T11:48:16-08:00">March  1, 2010 11:48 AM</abbr>
  54
  55                                         </span>
  56
  57
  58                                     </div>
  59                                 </div>
  60                                 <div class="asset-content entry-content">
  61
  62                                     <div class="asset-body">
  63                                         <p>This seems to be the trend now a days in Corporate IT. Is it just Windows related? I don't know. It used to be that you could rely on DNS. Now you can't. Case in point - people hear talk about a machine known as "seacase". Others use the name usseacase. Whicih is correct? Well an educated guess would be they are one in the same and a DNS alias exists between them. IOW seacase is just a "pretty" name for usseacase.</p>
  64
  65 <p>Now I used to be that you could verify that with DNS, in particular you could use nslookup to find each of the names and see they have the same IP address. But more and more, Corporate IT DNS stuff is screwed up, perhaps in the name of security, such that they don't always resolve:</p>
  66
  67 <div class=code>$ nslookup usseacase
  68 Non-authoritative answer:
  69 Server:  &lt;dns server>
  70 Address:  13.230.100.200
  71
  72 <p>Name:    usseacase.&lt;domain>.com<br />
  73 Address:  13.230.100.74<br />
  74 </div></p>
  75
  76 <p>So we can look that one up but we can't lookup the other:</p>
  77
  78 <div class=code>$ nslookup seacase
  79 *** &lt;dns server> can't find seacase: Non-existent domain
  80 Server:  &lt;dns server>
  81 Address:  13.230.100.200
  82 </div>
  83
  84 <p>However ping works! And verifies that this is the same machine. So why doesn't DNS know about this?</p>
  85
  86 <div class=code>$ ping seacase
  87 PING seacase (13.230.100.74): 56 data bytes
  88 64 bytes from 13.230.100.74: icmp_seq=0 ttl=127 time=230 ms
  89 64 bytes from 13.230.100.74: icmp_seq=1 ttl=127 time=0 ms
  90
  91 <p>----seacase PING Statistics----<br />
  92 2 packets transmitted, 2 packets received, 0.0% packet loss<br />
  93 round-trip (ms)  min/avg/max/med = 0/115/230/115<br />
  94 </div></p>
  95
  96 <p>Another pet peave of mine is people using either IP addresses instead of names (Do you refer to your friends by their cell phone numbers?) or using fully qualified machine names all the time when you don't need to...</p>
  97                                     </div>
  98
  99
 100                                 </div>
 101                                 <div class="asset-footer">
 102
 103
 104
 105
 106                                 </div>
 107                             </div>
 108
 109
 110
 111
 112
 113
 114                         </div>
 115                     </div>
 116
 117
 118                     <div id="beta">
 119     <div id="beta-inner">
 120
 121
 122
 123     <div class="widget-archive widget-archive-category widget">
 124     <h3 class="widget-header">Categories</h3>
 125     <div class="widget-content">
 126
 127     </div>
 128 </div>
 129
 130
 131
 132
 133     <div class="widget-archive-monthly widget-archive widget">
 134     <h3 class="widget-header">Monthly <a href="http://defaria.com/blogs/General/archives.html">Archives</a></h3>
 135     <div class="widget-content">
 136         <ul>
 137
 138             <li><a href="http://defaria.com/blogs/General/archives/2017/07/">July 2017 (1)</a></li>
 139
 140
 141
 142             <li><a href="http://defaria.com/blogs/General/archives/2017/04/">April 2017 (1)</a></li>
 143
 144
 145
 146             <li><a href="http://defaria.com/blogs/General/archives/2016/11/">November 2016 (1)</a></li>
 147
 148
 149
 150             <li><a href="http://defaria.com/blogs/General/archives/2016/05/">May 2016 (1)</a></li>
 151
 152
 153
 154             <li><a href="http://defaria.com/blogs/General/archives/2016/03/">March 2016 (1)</a></li>
 155
 156
 157
 158             <li><a href="http://defaria.com/blogs/General/archives/2015/10/">October 2015 (1)</a></li>
 159
 160
 161
 162             <li><a href="http://defaria.com/blogs/General/archives/2015/01/">January 2015 (2)</a></li>
 163
 164
 165
 166             <li><a href="http://defaria.com/blogs/General/archives/2014/11/">November 2014 (1)</a></li>
 167
 168
 169
 170             <li><a href="http://defaria.com/blogs/General/archives/2014/02/">February 2014 (1)</a></li>
 171
 172
 173
 174             <li><a href="http://defaria.com/blogs/General/archives/2014/01/">January 2014 (1)</a></li>
 175
 176
 177
 178             <li><a href="http://defaria.com/blogs/General/archives/2011/03/">March 2011 (1)</a></li>
 179
 180
 181
 182             <li><a href="http://defaria.com/blogs/General/archives/2010/11/">November 2010 (1)</a></li>
 183
 184
 185
 186             <li><a href="http://defaria.com/blogs/General/archives/2010/10/">October 2010 (1)</a></li>
 187
 188
 189
 190             <li><a href="http://defaria.com/blogs/General/archives/2010/06/">June 2010 (4)</a></li>
 191
 192
 193
 194             <li><a href="http://defaria.com/blogs/General/archives/2010/04/">April 2010 (1)</a></li>
 195
 196
 197
 198             <li><a href="http://defaria.com/blogs/General/archives/2010/03/">March 2010 (4)</a></li>
 199
 200
 201
 202             <li><a href="http://defaria.com/blogs/General/archives/2010/02/">February 2010 (7)</a></li>
 203
 204
 205
 206             <li><a href="http://defaria.com/blogs/General/archives/2009/05/">May 2009 (1)</a></li>
 207
 208
 209
 210             <li><a href="http://defaria.com/blogs/General/archives/2009/04/">April 2009 (2)</a></li>
 211
 212
 213
 214             <li><a href="http://defaria.com/blogs/General/archives/2009/01/">January 2009 (1)</a></li>
 215
 216
 217
 218             <li><a href="http://defaria.com/blogs/General/archives/2007/04/">April 2007 (1)</a></li>
 219
 220
 221
 222             <li><a href="http://defaria.com/blogs/General/archives/2006/11/">November 2006 (1)</a></li>
 223
 224
 225
 226             <li><a href="http://defaria.com/blogs/General/archives/2006/09/">September 2006 (2)</a></li>
 227
 228
 229
 230             <li><a href="http://defaria.com/blogs/General/archives/2005/12/">December 2005 (1)</a></li>
 231
 232
 233
 234             <li><a href="http://defaria.com/blogs/General/archives/2005/10/">October 2005 (1)</a></li>
 235
 236
 237
 238             <li><a href="http://defaria.com/blogs/General/archives/2005/09/">September 2005 (1)</a></li>
 239
 240
 241
 242             <li><a href="http://defaria.com/blogs/General/archives/2005/08/">August 2005 (1)</a></li>
 243
 244
 245
 246             <li><a href="http://defaria.com/blogs/General/archives/2005/03/">March 2005 (1)</a></li>
 247
 248
 249
 250             <li><a href="http://defaria.com/blogs/General/archives/2004/02/">February 2004 (6)</a></li>
 251
 252
 253
 254             <li><a href="http://defaria.com/blogs/General/archives/2004/01/">January 2004 (1)</a></li>
 255
 256
 257
 258             <li><a href="http://defaria.com/blogs/General/archives/2003/11/">November 2003 (2)</a></li>
 259
 260
 261
 262             <li><a href="http://defaria.com/blogs/General/archives/2003/10/">October 2003 (5)</a></li>
 263
 264         </ul>
 265     </div>
 266 </div>
 267
 268
 269
 270
 271
 272 <div class="widget-pages widget">
 273     <h3 class="widget-header">Pages</h3>
 274     <div class="widget-content">
 275         <ul>
 276
 277
 278             <li class="folder folder-38"><strong>about</strong>
 279
 280             </li>
 281
 282
 283         </ul>
 284     </div>
 285 </div>
 286
 287 <div class="widget-syndication widget">
 288     <div class="widget-content">
 289         <ul>
 290             <li><img src="http://defaria.com/mt/mt-static/images/status_icons/feed.gif" alt="Subscribe to feed" width="9" height="9" /> <a href="http://defaria.com/blogs/General/atom.xml">Subscribe to this blog's feed</a></li>
 291
 292         </ul>
 293     </div>
 294 </div>
 295 <div class="widget-powered widget">
 296     <div class="widget-content">
 297         <a href="http://www.movabletype.com/"><img src="http://defaria.com/mt/mt-static/images/bug-pbmt-white.png" alt="Powered by Movable Type 5.2.3" width="120" height="75" /></a>
 298     </div>
 299 </div>
 300
 301
 302
 303     </div>
 304 </div>
 305
 306
 307
 308
 309 <div id="gamma">
 310     <div id="gamma-inner">
 311     <div class="widget-search widget">
 312     <h3 class="widget-header">Search</h3>
 313     <div class="widget-content">
 314         <form method="get" action="http://defaria.com/mt/mt-search.cgi">
 315             <input type="text" id="search" class="ti" name="search" value="" />
 316
 317             <input type="hidden" name="IncludeBlogs" value="1" />
 318
 319             <input type="hidden" name="limit" value="20" />
 320             <input type="submit" accesskey="4" value="Search" />
 321         </form>
 322     </div>
 323 </div>
 324
 325 <div class="widget-about-this-page widget">
 326     <h3 class="widget-header">
 327
 328         About this Entry
 329
 330
 331     </h3>
 332     <div class="widget-content">
 333
 334
 335         <p class="first">This page contains a single entry by  published on <em>March  1, 2010 11:48 AM</em>.</p>
 336
 337         <p><a href="http://defaria.com/blogs/General/archives/2010/02/making-it-way-h.html">Making it way harder than it needs to be</a> was the previous entry in this blog.</p>
 338
 339
 340         <p><a href="http://defaria.com/blogs/General/archives/2010/03/priority-queues.html">Priority Queues...</a> is the next entry in this blog.</p>
 341
 342
 343
 344
 345
 346
 347         <p>Find recent content on the <a href="http://defaria.com/blogs/General/">main index</a> or look in the <a href="http://defaria.com/blogs/General/archives.html">archives</a> to find all content.</p>
 348
 349     </div>
 350 </div>
 351
 352
 353     </div>
 354 </div>
 355
 356
 357
 358
 359                 </div>
 360             </div>
 361
 362
 363             <div id="footer">
 364     <div id="footer-inner">
 365         <div id="footer-content">
 366             <div class="widget-powered widget">
 367                 <div class="widget-content">
 368                     Powered by <a href="http://www.movabletype.org/">Movable Type</a>
 369                 </div>
 370             </div>
 371
 372         </div>
 373     </div>
 374 </div>
 375
 376
 377
 378         </div>
 379     </div>
 380 </body>
 381 </html>