Reverse DNS lookup linux
PTR record for an IP address
dig +short -x 8.8.8.8
more linux
all 133 commands →
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
Test MTU path
ping -M do -s 1472 -c 3 8.8.8.8