ping.eu Online Ping, Port check, WHOIS, DNS lookup
my-addr.com/ip View HTTP_VIA proxy tag
DomainDossier Investigate domains and IP addresses
www.kloth.net/services DIG: look up DNS domain IP address information
web-sniffer.net View HTTP Request and Response Header
www.coffer.com/mac_find Match your MAC address to its vendor
www.kitterman.com/spf SPF Record Testing Tools
www.sslshopper.com/ssl-converter OpenSSL Commands to Convert SSL Certificates
Network Monitoring Tools List of tools used for Network Monitoring tools
av-test.org Antivirus tests
MonkeyBuk blog