View and Clear the DNS Cache on Windows (ipconfig /displaydns)
See which domains your PC has looked up recently and clear stale DNS answers with two built-in commands.
विषय
DNS
Reset the Windows Network Stack When the Internet Feels Slow
Three built-in commands that clear DNS, reset TCP/IP and Winsock – the fix for many “connected but slow” problems.
Fix “opendkim-testkey: unexpected reply class/type (-1/-1)”
OpenDKIM can’t look up your DKIM record. Give it working DNS resolvers with the Nameservers setting, restart and test again.