<div>Good morning Damon!</div>
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<div>As far as I can tell by editing /etc/hosts on a RHEL 4 box, the IP addresses are not cached longer than it takes me to edit the file. I believe your server will alwyas look in /etc/hosts anyway, per the /etc/nsswitch.conf file. The normal hosts line is something like:
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<div> hosts: files dns<br></div></div>
<div>There is the program nscd and it's config file, ncsd.conf. This configures some caching for you but I *think* it's more DNS related than affecting /etc/hosts. </div>
<div>Hope that helps.</div>
<div> </div>
<div>Leam<br><br></div>
<div class="gmail_quote">On Fri, Nov 4, 2011 at 7:40 AM, Chesser.Damon <span dir="ltr"><<a href="mailto:Damon.Chesser@suntrust.com">Damon.Chesser@suntrust.com</a>></span> wrote:<br>
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<p class="MsoNormal">This dovetails into building a DNS caching server I asked earlier this week. The issue is we are seeing latency in our application and a possible (but only possible, not proven) issue might be host lookups. I figured that an entry into /etc/hosts would be faster than a WAN DNS lookup especially since the IP is static. Someone was concerned with disk reads and that becoming a bottleneck. Someone else pointed out that /etc/hosts file was cached. <u></u><u></u></p>
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<p class="MsoNormal">This started a google search by me to find out if that was true or not. Totally inconclusive. Some have reported issues with not being able to get the Linux box to re-read the hosts file after a change was committed short of a reboot or init restart. Others have said just make the change and it shows up. I have not found any documentation saying whether it was cached or not. Any smart guys know the answer or can provide any documentation on that? It’s kind of funny, you think you KNOW something until someone says “Prove it”.<u></u><u></u></p>
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<p class="MsoNormal"><a href="mailto:Damon@damtek.com" target="_blank">Damon@damtek.com</a><u></u><u></u></p>
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