About Computer Network Checker
Computer Network Checker is a free suite of online network diagnostic tools designed for anyone who needs to understand how their network works — from home users troubleshooting connectivity problems to IT professionals auditing infrastructure. Based in Ontario, Canada, we are committed to providing fast, reliable, and easy-to-understand network utilities.
Our Mission
Most network utilities show raw data with no context. A DNS lookup returns a list of IP addresses. A port scan returns "open" or "closed." But what does that mean for someone who just wants to fix their email or check if their server is reachable?
We built Computer Network Checker to fill that gap. Every tool explains what the results mean in plain language and suggests what to do next. Our goal is simple:
Check your network. Understand the results. Know what to do next.
Our Tools
- Subnet Calculator — Calculate subnet masks, network addresses, broadcast addresses, and usable host ranges from any IP and CIDR prefix.
- What Is My IP — Look up the approximate geographic location, ISP, and ASN for any public IP address. Your own public IP is shown automatically when you visit the tool.
- DNS Lookup Tool — Query A, AAAA, MX, TXT, NS, CNAME, and SOA records for any domain with plain-language explanations of what each record type means and how to troubleshoot common issues.
- Ping & Traceroute — Measure latency to a server and trace the routing path that packets take. Tests run from our infrastructure, not from your device.
- Port Checker — Test whether common TCP ports are open, closed, or filtered on any public IP or domain. Useful for basic firewall audits and verifying that services are reachable.
- IP WHOIS Lookup — Check domain registration details including registrar, creation date, expiry date, status codes, and authoritative name servers.
- SSL Certificate Checker — Verify SSL/TLS certificate validity, issuer, expiry date, protocol version, and subject alternative names for any website.
Accuracy and Limitations
IP geolocation is approximate. It identifies the location registered by the Internet Service Provider, which is typically accurate at the country level and roughly accurate at the city level. It cannot identify a physical street address.
Ping, traceroute, and port-check results reflect the network path and reachability from our infrastructure — not from your device. Your own results may differ depending on your ISP, location, and local network configuration.
Who We Serve
Computer Network Checker is used by a wide range of people and organizations:
- Home users troubleshooting slow connections, DNS issues, or checking if a service is reachable
- Small business owners verifying their website's DNS configuration or confirming that their servers are accessible
- IT professionals auditing firewall rules, verifying DNS propagation, and planning IP address allocation
- Students and educators learning about networking concepts like subnetting, DNS resolution, and network routing
Contact
If you have questions, suggestions, or feedback, we would love to hear from you.
Email: info@computernetworkchecker.com
Location: Ontario, Canada