我妻子告诉我，当她在电脑上键入错误时，我的脸就会出现在屏幕上。经过一番思考，我意识到她指的是我配置的[url=www.opendns.com]OpenDNS[/url]页面。我认为OpenDNS很棒,我开始使用后发现的引用在[url = http://www.polarcloud.com/tomato]番茄firware [/ url]的[url = http://www.linksys.com/servlet/Satellite?c=L_Product_C2&childpagename=US%2FLayout&cid=1133202177241&pagename=Linksys%2FCommon%2FVisitorWrapper] WRT54GL [/ url]。配置在WRT54GL上的OpenDNS为我的家庭网络提供了很好的保护。我认为它比一些企业网络中安装的网络过滤软件更有效、更安全。这个事件让我想起了我遇到的一个严重的DNS问题。我到了办公室，老板把我领到了交易台。在那里我遇到了混乱。
这个场景深深地印在我的脑海里，因为DBA刚刚经历了一场车祸，他的头皮被钉住，使他看起来像一个[url=http://memory-alpha.org/en/wiki/Borg_Collective]Borg collective[/url]。他说他已经重新启动了站点上的每个服务器，由于他的交易应用程序仍然不能工作，一定是我在网络上做了一个改变。他的老板发现了这一点，开始斥责我在没有任何变更控制授权的情况下进行变更。在他身后，一群毒品贩子似乎正在组成一群私刑暴民。幸运的是，我的老板就站在我旁边，他安抚了他们，而我去拿我的笔记本电脑，现在，Wireshark[/url]。我想对这个问题进行包捕获，因为初步测试表明所有网络连接都没问题。我用处理应用程序完成了问题的包捕获，有趣的是，它的名称类似于墨西哥啤酒。我在跟踪中看到的第一件事是大量的DNS包和其他的。我看了DNS包，看到应用程序正在做DNS查询的IP地址的主应用程序服务器，“10.0.32.99”，这是失败的，然后它继续尝试“10.0.32.99.company.co.za”，这也失败了。下一个查询是“10.0.32.99.co”。za" which replied with an Internet IP address translation. The application then tried to connect to this address and the firewall kicked in and dropped these packets. The puzzle pieces started falling into place. The application was programmed to do a DNS query and if that did not succeed then use the IP address directly. Bad strategy as it turned out! It also explained why the DBA kept on complaining about slow logons, which I always assumed was application related. I also discovered that the previous night a company had registered the domain "99.co.za" They also had a wildcard for all hosts in that domain. The underlying problem was always there, waiting to bite. We fixed the problem by setting up the application the way it should have been done the first time round. We created a DNS record for the main dealing application server of "mexicanbeer.company.co.za" and configured the application on all the client computers to use this instead of the IP address. The dealing desks started returning to normal and the manager of the dealing desks walked over to ask as to the cause of the problem. After explaining it to him, he replied that he was then correct in stating that an unauthorised change had been made and we should not do that again. I tried to explain that we had no input into authorizing domains on the Internet and that was done indepemtely by the service providers. His comment was that how dare anyone use "99.co.za" when it was his. I started trying to explain the difference between IP addresses and DNS domains, his eyes glazed over, and I knew it was a lost cause. Finally, I told him I would phone up our service provider and tell them to cease and desist from doing it again. These and other experiences, have resulted in me creating a [url=http://thinkingproblemmanagement.blogspot.com/2007/10/ultimate-test-pilots.html]network troubleshooting checklist[/url]. This whole episode brings to the fore a question in my mind as to how do you deal with explaining a technical cause to someone who has no idea as to what you are on about? Do you do like me, and lie through your teeth?