There are cases where you want to monitor a specific type of connection going from/to & through your router. As an example the following example keeps track of DNS requests towards name servers.

watch -tn5 “conntrack -L -p udp –dport 53 | sort -nrk3; echo; conntrack -L -p tcp –dport 53 | sort -nrk3”

53 of course refers to DNS and in the above case includes both udp and tcp. You can change this to any port of relevancy (e.g. 443 tcp only) to change the command scope. e.g.

watch -tn5 “conntrack -L -p tcp –dport 443 | sort -nrk3”