Just use Netstat -a to see connections. Open command prompt, type netstat -a
Remember, without DNSClient your resolution will not be cached unless you have another program or piece of hardware caching resolutions. Your browser is ALREADY caching resolutions, so DNSClient is redundant and even slows down browsing in some cases added a secondary and unnecessary call. Chrome for example has a DNS Preresolver so once the DNS resolution is established from primary forwarder, you are much better off than using DNSClient.
For non-browsers, DNS resolution without a cache/resolver will be imperceptibly slower. Ping your DNS and find your non-browser cache speed, usually sub-20ms, something you likely won't perceive. For example if you launch a game it's resolving already during the launch period so a >20ms resolution poll won't be perceptible AT ALL..
If you have a local DNS (Pi-Hole, strongly recommended), DNSClient WILL slow everything down because it's adding a second or third layer, totally unnecessary cache to your system. If you use Heimdal, it's adding ANOTHER dns cache because Heimdal itself has a small caching agent from your primary resolver so DNSClient once again gets in your way.
We know over the years, that things like DNSClient are junk and should be disabled..
Flaw in Windows DNS client exposed millions of users to hacking
Microsoft Windows DNS Client Buffer Overflow Vulnerability
Microsoft Windows DNS Client Service Response Spoofing Vulnerability | | Norton
https://support.microsoft.com/en-us...nerability-in-dns-client-could-allow-spoofing