Fetch HTTP headers only
Fetches only the HTTP response headers.
curl -I https://example.comNetworking commands
17 commands from the cloud runbook. Fill in a placeholder once and every command uses it.
Trace DNS resolution path
Follows the DNS delegation path from root servers.
dig +trace <domain>Test TCP port connectivity
Uses netcat to check if a remote TCP port is reachable.
nc -vz <hostname> <port>Capture packets on port
Captures and displays raw network traffic on a specific port.
sudo tcpdump -i any port 80 -n -vCheck a remote TLS certificate's expiry
Fetches and displays the expiration date of a remote SSL certificate.
echo | openssl s_client -servername example.com -connect example.com:443 2>/dev/null | openssl x509 -noout -datesFormat JSON with jq
Fetches a JSON API response and formats it nicely using jq.
curl -s https://api.github.com/users/octocat | jq '.'Test Nginx configuration
Tests the Nginx config files for syntax errors before reloading.
sudo nginx -tReload Nginx gracefully
Reloads the Nginx configuration without dropping active connections.
sudo nginx -s reloadMonitor Nginx access logs
Tails the Nginx access logs and uses awk to show only IPs and HTTP status.
tail -f /var/log/nginx/access.log | awk '{print $1, $9}'Check IP routing
Determines exactly which interface and route will be used to reach an IP.
ip route get 8.8.8.8Ping via specific interface
Forces ping to use a specific network interface.
ping -I eth1 8.8.8.8Network path analysis (mtr)
Combines ping and traceroute for real-time network path analysis.
mtr --report <hostname>List iptables rules
Shows all current iptables firewall rules with line numbers.
sudo iptables -L -n -v --line-numbersDNS lookup
Queries a DNS server to resolve a domain name.
nslookup <domain> 8.8.8.8Mirror a website with wget
Downloads an entire website for offline browsing.
wget --mirror --convert-links --page-requisites <url>Send POST request with JSON
Sends a JSON payload to an API endpoint.
curl -X POST -H "Content-Type: application/json" -d '{"key":"value"}' https://api.example.com/endpointWHOIS domain lookup
Fetches domain registration information.
whois example.com