Network Connectivity Tools
Free diagnostic tools and related guides for checking Network Connectivity issues in one place.
What should I check first for Network Connectivity issues?
For Network Connectivity issues, start with Check My IP Address to capture the current state, then use IP Trace to narrow the cause. If the result is unclear, read the related guide and open the next tool before changing settings.
Recommended Check Order
Open the tools in this order to narrow the issue before you change DNS, email, security, privacy, or network settings.
Check the current state: Check My IP Address
Instantly check your public IPv4/IPv6 address, ISP, and approximate location.
Narrow the cause: IP Trace
Look up country, city, ISP, and ASN details for an IP address.
Cross-check the result: Ping Test
Measure round-trip latency to known endpoints and custom hosts.
Common Symptoms
Common problem patterns grouped by tool. If a symptom matches, start with that check.
IPv6 is available, but the current connection shows IPv4.
Check whether the target site returned AAAA records and whether browser, VPN, or ISP policy sent this request over IPv4.
Compare DNS leak and WebRTC signals to see whether the same public address is exposed elsewhere.
The same target behaves differently on another network.
ISP, DNS cache, CDN routing, VPN, firewall, and NAT paths can change lookup and latency results.
Compare current IP, ASN, and trace results to locate where the path changes.
The same target behaves differently on another network.
ISP, DNS cache, CDN routing, VPN, firewall, and NAT paths can change lookup and latency results.
Compare current IP, ASN, and trace results to locate where the path changes.
The service runs on the server, but the public port looks closed.
Process listen state, external firewall, cloud security groups, and router port forwarding are separate layers.
Use port check with ping/IP trace and headers to separate network reachability from application behavior.
The IP network owner is not what you expected.
A CDN, VPN, proxy, or cloud load balancer may route the visible request through another ASN.
Compare IP lookup and current IP results to separate origin, CDN, and proxy paths.
The same target behaves differently on another network.
ISP, DNS cache, CDN routing, VPN, firewall, and NAT paths can change lookup and latency results.
Compare current IP, ASN, and trace results to locate where the path changes.
Which tool should I open first?
Use this matrix to match the symptom to the right tool, the signal to check, and the next action.
Check My IP Address
Instantly check your public IPv4/IPv6 address, ISP, and approximate location.
Use the Check My IP Address result to narrow Network Connectivity issues.
After reviewing the result, cross-check it with a related tool or guide.
IP Trace
Look up country, city, ISP, and ASN details for an IP address.
Use the IP Trace result to narrow Network Connectivity issues.
After reviewing the result, cross-check it with a related tool or guide.
Ping Test
Measure round-trip latency to known endpoints and custom hosts.
Use the Ping Test result to narrow Network Connectivity issues.
After reviewing the result, cross-check it with a related tool or guide.
Port Scanner
Test whether a target TCP port is open, closed, or filtered.
Use the Port Scanner result to narrow Network Connectivity issues.
After reviewing the result, cross-check it with a related tool or guide.
ASN Lookup
Lookup ASN ownership and network range details for an IP.
Use the ASN Lookup result to narrow Network Connectivity issues.
After reviewing the result, cross-check it with a related tool or guide.
WHOIS / DNS Lookup
Look up WHOIS ownership data and core DNS records.
Use the WHOIS / DNS Lookup result to narrow Network Connectivity issues.
After reviewing the result, cross-check it with a related tool or guide.
How To Choose The Right Tool
Chrome “This Site Can’t Be Reached”: Causes and Fixes
Chrome “This site can’t be reached” is a broad symptom, not one root cause. DNS failures, timeouts, refused ports, server outages, proxy or VPN issues, routing problems, and SSL errors can all appear under this message.
Port Scanner
Test whether a target TCP port is open, closed, or filtered.
Frequently Asked Questions
Network Connectivity: what should I check first?
For Network Connectivity issues, start with Check My IP Address to capture the current state, then use IP Trace to narrow the cause. If the result is unclear, read the related guide and open the next tool before changing settings.
Which tools should I run first?
Run Check My IP Address, IP Trace, Ping Test in that order to separate current state, likely cause, and cross-check signals.
What should I read if the result is unclear?
If the result is unclear, open Chrome “This Site Can’t Be Reached”: Causes and Fixes and review the same problem as a checklist.
Tools To Run
Check My IP Address
Instantly check your public IPv4/IPv6 address, ISP, and approximate location.
IP Trace
Look up country, city, ISP, and ASN details for an IP address.
Ping Test
Measure round-trip latency to known endpoints and custom hosts.
Port Scanner
Test whether a target TCP port is open, closed, or filtered.
ASN Lookup
Lookup ASN ownership and network range details for an IP.
WHOIS / DNS Lookup
Look up WHOIS ownership data and core DNS records.
Subnet Calc
Calculate subnet mask, network range, and host capacity from CIDR.
IP Converter
Convert IP values between dotted, binary, hex, and integer forms.
MAC Vendor Lookup
Resolve MAC OUI prefixes to vendor information.
Hardware Info
Review hardware signals such as CPU cores and memory hints.
Guides To Read
Chrome “This Site Can’t Be Reached”: Causes and Fixes
Chrome “This site can’t be reached” is a broad symptom, not one root cause. DNS failures, timeouts, refused ports, server outages, proxy or VPN issues, routing problems, and SSL errors can all appear under this message.
Wi-Fi Connected but No Internet: Causes and Fixes
“Wi-Fi connected but no internet” means the device joined the wireless network but still cannot reach the internet. Router state, DNS, ISP outage, captive portal login, VPN, IPv6, proxy, and local cache should be separated.
Public Wi-Fi Login Page Not Opening: Causes and Fixes
When a public Wi-Fi login page does not open, the device may be connected to the network but not yet authorized for internet access. HTTPS redirects, DNS, browser cache, VPN, proxy, cookies, and captive portal detection should be checked.
VPN Connected but No Internet: Causes and Fixes
A VPN can show connected while the actual internet route is broken. Kill switch state, DNS, split tunneling, IPv6, proxy settings, VPN server health, and corporate network policy should be separated.
Mobile Data Not Working: Causes and Fixes
Mobile data failures can come from carrier signal, plan limits, APN settings, DNS, IPv6, VPN, tethering mode, or browser cache. Separate Wi-Fi from cellular and compare current IP, DNS, and route behavior.
ERR_HTTP2_PROTOCOL_ERROR: Causes and Fixes
ERR_HTTP2_PROTOCOL_ERROR means the browser hit a protocol-level problem while handling an HTTP/2 connection with a server, CDN, or proxy. Compression headers, CDN edge behavior, TLS, server push, gRPC, WAF rules, cache, and recent deployments can all be involved.
PR_CONNECT_RESET_ERROR: Causes and Fixes
PR_CONNECT_RESET_ERROR appears in Firefox when an HTTPS connection is reset before it can complete. TLS, proxy settings, VPN, security software HTTPS inspection, server resets, CDN origin connectivity, and firewalls should be checked together.
ERR_CONNECTION_ABORTED: Causes and Fixes
ERR_CONNECTION_ABORTED means the browser started a connection but it was cancelled or cut off along the path. Server resets, proxies, VPNs, firewalls, CDN-to-origin issues, large response limits, browser extensions, and network changes should be separated.
ERR_CONNECTION_FAILED: Causes and Fixes
ERR_CONNECTION_FAILED is a broad Chrome error for a connection that could not be established. DNS, open ports, firewalls, proxies, VPNs, SSL, CDN status, and origin availability should be narrowed in order.
ERR_PROXY_CONNECTION_FAILED: Causes and Fixes
ERR_PROXY_CONNECTION_FAILED appears when the browser cannot reach a site through the configured proxy. Wrong proxy addresses, PAC files, authentication failures, VPN policy, corporate security gateways, DNS, and HTTPS tunnel failures should be separated.
ERR_QUIC_PROTOCOL_ERROR: Causes and Fixes
ERR_QUIC_PROTOCOL_ERROR appears when Chrome fails while handling a QUIC or HTTP/3 connection. UDP 443 blocking, CDN HTTP/3 settings, TLS, proxy or VPN paths, firewalls, browser cache, and extensions should be checked together.
ERR_NETWORK_CHANGED: Causes and Fixes
ERR_NETWORK_CHANGED appears when the browser detects that the network path changed while a page was loading. Wi-Fi switching, VPN connect or disconnect events, proxies, IPv4/IPv6 route changes, DNS resolver changes, and unstable routers can all trigger it.
ERR_INTERNET_DISCONNECTED: Causes and Fixes
ERR_INTERNET_DISCONNECTED appears when the browser cannot find a usable path to the internet. Device networking, router state, ISP outages, VPN kill switches, proxies, and DNS failures should be separated before treating it as a website outage.
DNS_PROBE_FINISHED_NO_INTERNET: Causes and Fixes
DNS_PROBE_FINISHED_NO_INTERNET appears when the browser cannot use DNS or an internet route reliably. Real internet disconnection, DNS resolver failure, VPN kill switches, proxies, router problems, and ISP outages should be separated.
ERR_ADDRESS_UNREACHABLE: Causes and Fixes
ERR_ADDRESS_UNREACHABLE appears when the browser cannot reach the target IP address or network route. Local routing, wrong IPs, VPN or proxy paths, routers, CGNAT, IPv6 behavior, and firewalls should be checked before treating the site as down.
ERR_EMPTY_RESPONSE: Causes and Fixes
ERR_EMPTY_RESPONSE appears when the browser connects but receives no usable HTTP response or body. Server process crashes, proxy or CDN disconnects, firewall drops, redirect conflicts, compression bugs, and malformed headers can all create the same browser symptom.
ERR_CONNECTION_RESET: Causes and Fixes
ERR_CONNECTION_RESET means the connection was established and then forcibly closed in the path. Server restarts, firewall reset rules, proxy or CDN timeouts, unstable VPN routes, MTU issues, HTTP/2, and TLS policy conflicts can all trigger it.
ERR_CONNECTION_CLOSED: Causes and Fixes
ERR_CONNECTION_CLOSED means the connection between the browser and server closed before the response finished. App shutdowns, reverse proxy closes, CDN origin issues, TLS or HTTP/2 conflicts, and security appliances can all cause it.
ERR_TUNNEL_CONNECTION_FAILED: Causes and Fixes
ERR_TUNNEL_CONNECTION_FAILED appears when the browser cannot create an HTTPS tunnel through a proxy or VPN path. Wrong proxy addresses, failed authentication, corporate blocking, split tunneling, DNS handling, and HTTPS inspection certificates should be checked together.
HTTP 502 Bad Gateway: Causes and Fixes
HTTP 502 Bad Gateway appears when a gateway, proxy, load balancer, or CDN receives an invalid response from the origin or upstream service. CDN edge behavior, reverse proxy rules, origin availability, DNS, SSL mode, and upstream ports should be separated.
HTTP 503 Service Unavailable: Causes and Fixes
HTTP 503 Service Unavailable means the service is temporarily unable to handle the request. Maintenance mode, overload, exhausted workers, rate limits, autoscaling delay, origin downtime, and CDN protection modes can all create this status.
HTTP 504 Gateway Timeout: Causes and Fixes
HTTP 504 Gateway Timeout appears when a gateway, proxy, CDN, or load balancer does not receive an upstream response in time. Origin latency, database queries, external APIs, routing delay, worker queues, and timeout settings should be checked together.
Cloudflare 521 Web Server Is Down: Causes and Fixes
Cloudflare 521 appears when Cloudflare tries to connect to the origin server but the origin refuses or cannot accept the connection. Stopped web servers, closed 80 or 443 ports, firewall rules, security groups, and blocked Cloudflare IP ranges should be checked first.
Cloudflare 522 Connection Timed Out: Causes and Fixes
Cloudflare 522 appears when Cloudflare cannot establish or maintain a TCP connection to the origin in time. Origin overload, route delay, firewall drops, routing problems, and slow port response should be checked before tuning the application alone.
Cloudflare 523 Origin Is Unreachable: Causes and Fixes
Cloudflare 523 appears when Cloudflare can identify the origin target but cannot reach that origin network. Stale origin IPs, broken routing, firewall rules, cloud security groups, and BGP or ASN path problems should be checked together.
Cloudflare 524 A Timeout Occurred: Causes and Fixes
Cloudflare 524 appears when Cloudflare establishes a connection to the origin but the origin does not finish the HTTP response in time. Slow database queries, external APIs, long jobs, worker shortage, cache misses, and timeout settings should be checked.
Cloudflare 1016 Origin DNS Error: Causes and Fixes
Cloudflare 1016 appears when Cloudflare cannot resolve the hostname configured as the origin. Missing A or AAAA records, deleted CNAME targets, wrong origin names, private DNS names, DNSSEC issues, and nameserver delegation should be checked first.
DNS_PROBE_FINISHED_BAD_CONFIG: Causes and Fixes
DNS_PROBE_FINISHED_BAD_CONFIG appears when the DNS configuration used by the browser is broken or unstable. Router DNS, operating-system DNS, browser Secure DNS, VPN DNS, corporate DNS, and DNS cache should be separated before changing site records.
DNS Server Not Responding: Causes and Fixes
“DNS server not responding” means the browser or operating system could not get a usable response from the resolver that turns names into IP addresses. Router DNS, ISP resolver outages, VPN DNS, Secure DNS, and broken domain records should be separated.
ERR_CONNECTION_REFUSED: Causes and Fixes
ERR_CONNECTION_REFUSED often means the target IP was reached but the destination port did not accept the connection. Stopped server processes, wrong ports, firewall reject rules, local dev servers, proxies, and CDN origin settings should be separated before changing DNS.
ERR_CONNECTION_TIMED_OUT: Causes and Fixes
ERR_CONNECTION_TIMED_OUT means the browser tried to connect but did not receive a response before the timeout. Server downtime, firewall rules, blocked ports, DNS delay, routing failure, CDN issues, and hosting outages can all look the same to visitors.
ERR_NAME_NOT_RESOLVED: Causes and Fixes
ERR_NAME_NOT_RESOLVED appears when the browser cannot resolve the hostname to an IP address. Misspelled domains, missing DNS records, nameserver propagation, corporate DNS, VPN DNS, and browser cache can all create the same visitor-facing error.
Server IP Address Could Not Be Found: Causes and Fixes
“Server IP address could not be found” means the browser could not translate the hostname into an IP address. Typos, missing www records, deleted DNS records, nameserver propagation, expired domains, and local DNS cache can all cause it.
Public IP vs Private IP: What Is the Difference?
A public IP is the address visible on the internet, while a private IP is used inside a router, home network, or office network. Understanding the difference helps explain VPN behavior, shared Wi-Fi, port forwarding, and why a device IP may not match what websites see.
Why Your IP Address Keeps Changing
A public IP can change because of ISP DHCP leases, router restarts, mobile-network movement, VPN server changes, CGNAT, or IPv4/IPv6 path changes. Understanding the cause helps interpret login alerts, access restrictions, port forwarding, and remote access issues.
Why Your IP Location Looks Wrong
IP location is an estimate based on network ownership, VPN exits, cloud routing, proxies, and GeoIP databases, not GPS. When the city or country looks wrong, separate a privacy leak from database lag, browser location permission, and account-location signals.
Why Your IP Is Blacklisted and How to Request Removal
An IP can appear on a blacklist because of spam, compromised accounts, infected devices, shared-hosting reputation, missing reverse DNS, or sudden sending spikes. Before requesting delisting, confirm the sending IP, mail authentication, reverse DNS, logs, and whether the IP is shared.
Why Port Forwarding Fails Behind CGNAT
Carrier-grade NAT lets an ISP share one public IPv4 address across many customers. Even correct router port forwarding can fail when an extra ISP NAT layer blocks inbound traffic before it reaches the home router.
Double NAT Port Forwarding: Why Inbound Access Fails
Double NAT happens when a modem, router, mesh system, or VPN gateway each performs NAT before traffic reaches the device. Forwarding only the closest router can leave the real inbound block one layer upstream.
Router WAN IP Is Private: What It Means
If the router WAN IP is in 10.x.x.x, 172.16-31.x.x, 192.168.x.x, or 100.64.0.0/10, another NAT layer may exist before your router. The public IP visible to websites can differ from the WAN IP shown in the router.
NAT Type Strict: Causes and Fixes for Gaming
Strict NAT on a console or PC game can break matchmaking, voice chat, and peer-to-peer sessions. Common causes include blocked ports, double NAT, CGNAT, firewall rules, UPnP conflicts, and VPN routing.
DDNS Not Updating to the Current Public IP
Dynamic DNS maps a changing public IP to a hostname, but it can point to a stale address when the client reports the wrong IP, DNS TTL keeps old records visible, or the router WAN IP differs from the real public IP.
High Ping, Latency, and Jitter: What to Check
High ping and unstable jitter can make games, video calls, remote work, and real-time apps feel broken even when download speed looks fine. Separate latency, variation, packet loss, Wi-Fi quality, VPN routing, and upstream path behavior before blaming one device.
Packet Loss Troubleshooting: Causes and Check Order
Packet loss means some network probes or responses do not arrive. Game stutter, broken voice calls, upload failures, and intermittent timeouts often come from loss and retransmission rather than simple bandwidth.
Traceroute Asterisks and Timeouts: What They Mean
Asterisks in traceroute do not automatically mean the route is broken. Some routers rate-limit or deprioritize ICMP TTL-expired replies while still forwarding real web traffic normally.
IPv6 Slower Than IPv4: Causes and What to Compare
IPv6 is not inherently always faster or slower than IPv4. ISP routing, DNS AAAA answers, CDN edge choice, VPN support, firewall policy, and MTU behavior can make the same site perform differently over the two address families.
Why IPv6 Is Not Detected
IPv6 may be absent because of ISP support, router mode, operating system settings, VPN policy, DNS answers, or server readiness. A working IPv4 connection does not prove IPv6 is available or being used.
IPv4 vs IPv6 Current Connection
A device can have both IPv4 and IPv6 available while the current web request still uses only one address family. Reading the Current badge separately from available addresses helps diagnose VPNs, ISP routing, DNS answers, and server IPv6 readiness.
ASN Basics and Network Routing
An ASN shows which network operator announces and controls an IP range. That makes ASN data useful for understanding ISPs, cloud networks, and traffic ownership.
Port Open Locally but Unreachable Publicly
A service can be listening on the server while the public port still looks closed because of a firewall, cloud security group, NAT rule, ISP block, or DNS pointing at the wrong host. Separate local listen state from public reachability.
Reverse DNS and PTR Records
Reverse DNS maps an IP address back to a hostname. PTR records matter for mail reputation, server identity, and log clarity, especially when forward-confirmed DNS also matches.
FAQ
Network Connectivity: what should I check first?
Which tools should I run first?
What should I read if the result is unclear?
Data Handling & Privacy
ipnawa is a diagnostics service. Inputs are used to produce results and are not intended for account-based profiling.
- Server-side tools (WHOIS, SSL, DNS, header checks) send your input domain/IP to our server for lookup.
- Browser-side tools (fingerprint, cookies, JavaScript) run primarily in your browser when supported.
- Standard web/server security logs may include IP address, timestamp, and User-Agent.
- Some checks call external providers such as ipinfo.io and bigdatacloud.net.
- Ads and non-essential cookies are loaded only after your consent choice.
External Processors
- ipinfo.io (IP/ASN/location lookups)
- bigdatacloud.net (reverse geocoding)
- Advertising partners (only after ad-consent acceptance)
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