Editing Domain Name System (section)

====Broken resolvers====
Some large ISPs have configured their DNS servers to violate rules, such as by disobeying TTLs, or by indicating that a domain name does not exist just because one of its name servers does not respond.<ref>{{cite web
|url = http://ask.slashdot.org/story/05/04/18/198259/providers-ignoring-dns-ttl
|title = Providers ignoring DNS TTL?
|publisher = [[Slashdot]]
|year = 2005
|access-date = 2012-04-07
}}</ref>

Some applications such as web browsers maintain an internal DNS cache to avoid repeated lookups via the network. This practice can add extra difficulty when debugging DNS issues as it obscures the history of such data. These caches typically use very short caching times on the order of one minute.<ref>{{cite web|url=http://dyn.com/web-browser-dns-caching-bad-thing/|title=Ben Anderson: Why Web Browser DNS Caching Can Be A Bad Thing|author=Ben Anderson|date=7 September 2011|access-date=20 October 2014}}</ref>

[[Internet Explorer]] represents a notable exception: versions up to IE 3.x cache DNS records for 24 hours by default. Internet Explorer 4.x and later versions (up to IE 8) decrease the default timeout value to half an hour, which may be changed by modifying the default configuration.<ref>{{cite web
|url = http://support.microsoft.com/default.aspx?scid=KB;en-us;263558
|title = How Internet Explorer uses the cache for DNS host entries
|publisher = [[Microsoft Corporation]]
|year = 2004
|access-date = 2010-07-25
}}</ref>

When [[Google Chrome]] detects issues with the DNS server it displays a specific error message.