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How to clear the local DNS cache in Windows, Mac OS and Linux

Symptom

At your computer, when you type in the name to a website or device (like a Server, Network Attached Storage, Smart Appliance, etc.) in your browser, terminal or application, but it can’t resolve it or it locates an unintended website or device, yet other computers around you are able to connect just fine.

Cause

To save search (lookup) time, your computer maintains a list of translated names to network address locally in what is called your DNS cache for a certain period of time, before it sends another query to your DNS server. When changes are made between names and network addresses your computer may still rely on its local DNS cache which may contain outdated information.

Purpose

By clearing your locally stored DNS cache, your computer is forced to inquire the name to address translation directly from your DNS server.

Prerequisites

1) For wired connections, verify your physical connection by unplugging and plugging the network cable connected to your network port on your computer and on the other end which connect to the network jack at your cube or wall outlet.
2) Verify that your computer has a proper IP Address, Subnet Mask and Router
3) Verify that your computer has the proper DNS Servers list and Search Domain(s)
Although this is not a prerequisite, it just makes good sense to check if other computers around you are able to successfully connect.

Solution

Windows

1) Click on the Windows menu and in the search field type cmd or powershell to bring up a command console
2) In the command console type in the following command then press the Enter key to execute:

ipconfig /flushdns

Mac OS

1) Log into a user account with administrator privileges
2) At the Finder click on the Edit menu and select New Finder Window
3) Navigate to Applications > Utilities and double-click on the Terminal application
4) Depending on which Operating System you are running type in the following command:

Sierra (10.12.x), El Capitan (10.11.x), Yosemite (10.10.4 only)

sudo killall -HUP mDNSResponder

Yosemite (10.10.0 – 10.10.3)

sudo discoveryutil mdnsflushcache

Maverics (10.9.x), Mountain Lion (10.8.x), Lion (10.7.x)

sudo killall -HUP mDNSResponder

Snow Leopard (10.6.x), Leopard (10.5.x)

sudo dscacheutil -flushcache

5) To execute the command press the Return key
6) Type in your password and press the Return key

Linux

Depending on which distribution you are running use either of the following commands:

/etc/init.d/named restart
/etc/init.d/nscd restart