Updated April 08, 2022 · Published January 28, 2018
Below are a few methods and tools to help troubleshoot DNS on a Mac. This includes displaying the current DNS configuration, clearing your DNS cache, how to query a DNS server, and to even view the current DNS cache.
Display DNS configuration
To display your DNS configuration, run the following command from a terminal.
Clear DNS cache
Sometimes you need to clear you DNS cache. In order to do this, run the following commands from a terminal. Depending on your browser, you may need to also close your browser and clear it's own cache.
sudo killall -HUP mDNSResponder sudo dscacheutil -flushcache
Query DNS with nslookup
If you need to do simple lookups you can use nslookup to query a DNS server for a response.
# query default DNS server nslookup saucepan.org # query Google's Public DNS Server nslookup server 18.104.22.168 saucepan.org
Query DNS with dig
If you need a more advanced view or need to trace the steps of DNS query, the dig tool is very useful.
# query all results dig saucepan.org ANY # query A records dig saucepan.org A # query MX records dig saucepan.org MX # query NS records dig saucepan.org NS # query using a specific nameserver dig @ns-166.awsdns-20.com saucepan.org # trace the path taken of a query dig saucepan.org +trace
View DNS cache
Open Console, select your local machine, and search for mDNSResponder. Then open a terminal and type the command below. This will dump the current DNS cache into the console window.
sudo killall -INFO mDNSResponder