Table of Contents
Check IPs
DNS & Mail
SSL & Ports
Email
Speed
Block Access
Network
Check IPs
Arul's Utilities (IP tracking, MAC address)
What is my IP
What is my IP address
Whois Lookup
What is my User Agent
SSL checker
Am I Behind A Proxy?
IP Location Finder
TRUE IP address ranges
Understanding TCP/IP addressing and subnetting basics
Find MAC Address Vendors
Check Email protection
DNS & Mail
Watch TV which is restricted to domestic IP
SPF, DKIM, DMARC
What's My DNS Server?
Verify DNS
Trace DNS Delegation
DNS Nameserver Spoofability Test
DNS propagation checker
Check nameservers used
Dig web interface
How to run your own DNS Resolving Server
Now-DNS: Free DynDNS service and clients
DNS Servers
SSL & Ports
SSL Checker
Port Forwarding Tester
Open Port Check Tool
Verifying Which Ports Are Listening
Email
Yahoo
Google Mail
Mail Settings
Mail Server
Enhance security for outgoing email (DKIM)
DKIM Record Check
How to Set Up DKIM in 3 Simple Steps
Speed
3BB Speed Test
Testing iperf through an SSH tunnel
Pingdom Website Speed Test
What is my browser's User Agent
Internet Explorer User Agents
GTmetrix
Block Access
Block China and Korea From Apache Based Servers or Forums with a .htaccess Blocklist
iptables blacklist script
The Beginner’s Guide to iptables, the Linux Firewall
Stop Traffic From China IP Addresses To Protect Your Web Server From Chinese Hackers
How to fix MySQL high CPU usage
IPdeny country block downloads
Block all Russia Public IP Addresses
4 Ways to Identify Who is Logged-In on Your Linux System