DNS lookup linux
Query A records via a specific DNS server
dig +short A example.com @8.8.8.8
more linux
all 133 commands →
Reverse DNS lookup
dig +short -x 8.8.8.8
Trace DNS delegation
dig +trace example.com
Show established TCP connections
ss -tnp state established
Count connections per state
ss -tan | awk 'NR>1{print $1}' | sort | uniq -c | sort -rn
Traceroute with MTU discovery
mtr --report --tcp --port 443 example.com