How to Flush BIND Cache

BIND is the most popular Domain Name System (DNS) server on the Internet. It is also the reference implementation of DNS protocols, meaning it always has the latest features first. DNS translates domain names such as "example.com" into Internet Protocol (IP) address such as "1.2.3.4." BIND caches DNS queries so that it can respond more quickly to future requests. Clearing the BIND cache is often necessary after making DNS changes so that clients can immediately access the updated domain name.

Instructions

1. Type "named -v" to get the version number of your BIND server.

2. Enter "sudo rndc flush" if you are running BIND 9.2.0 or newer. This will clear the cache without restarting the BIND server.

3. Type "sudo rndc restart" if you are running a BIND version older than 9.2.0. This will kill the running BIND server and restart.

Tips & Warnings

• Prefix the commands with "su -c" instead of "sudo" if you are running a Fedora, CentOS or Red Hat server.

References

• Internet Systems Consortium: BIND
• O'Reilly: Cooking with DNS & BIND