My IP Check
Your public IP address and network location, detected automatically.
Loads automatically when you open NetChecks — no input needed. Use the Refresh button to re-check after switching networks or reconnecting your VPN.
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All-in-One Scan
Runs every relevant check against one IP or hostname in a single pass: DNS, whois, ping, traceroute, a well-known-ports scan (1-1024), HTTP headers and the SSL certificate.
Enter a domain or IP address and run it to check DNS, whois, ping, traceroute, common ports, HTTP headers, and the SSL certificate all at once.
Most checks run in parallel - typically finishes in about 30 seconds, longer if the target is slow or unreachable.
The port scan step only runs once the consent checkbox above is checked - every other check runs regardless.
Ping
Send ICMP echo requests to a host to check reachability and latency.
Enter a hostname or IP address and press Ping to send ICMP echo requests and measure round-trip latency.
Traceroute
Trace the network path (hop by hop) to a destination host.
Enter a hostname or IP address and run it to see every network hop between this server and the destination, with latency per hop.
Learn more about Traceroute
What it is
Traceroute reveals the full path taken by packets between your test point and the target, hop by hop (router by router), identifying the IP address of each router along the way and the response time measured at that exact point in the journey. Where Ping only gives you a single end-to-end result, Traceroute breaks that journey down into as many segments as there are intermediate routers, which makes it the go-to tool for pinpointing exactly where, on a network path that can sometimes run ten to twenty hops long, a problem is actually occurring.
How it works
The tool cleverly reuses the same TTL mechanism as Ping, but in reverse: it sends a series of packets with a deliberately increasing TTL, starting at 1. The first router receives a packet with TTL=1, decrements it to 0, drops it, and sends back an ICMP "Time Exceeded" message before even forwarding it further - revealing its address to the sender without needing to be the actual destination. By repeating this with an incrementing TTL each time (2, then 3, then 4...), each intermediate router reveals itself in turn, until the TTL is finally high enough to reach the actual destination, which then responds differently (typically with an ICMP Echo Reply or a port rejection, depending on the probe protocol used).
Reading the results
Latency that increases gradually hop after hop is entirely normal and expected: it simply reflects geographic distance and the number of routers crossed, each adding an unavoidable processing delay. A single hop showing a latency spike, with no impact on the hops that follow, is very often a router that deliberately treats ICMP as low priority (by design, so it does not slow down its actual routing job) rather than a genuine problem with the path at that point - a classic interpretation trap. Asterisks (* * *) on one or more consecutive hops simply mean those routers do not respond to ICMP at all, which is common as a matter of security policy and harmless as long as the following hops respond normally and the final destination is actually reached; it is only a real problem if the path stops completely at that point and never gets to the target.
Common mistakes
A common mistake is treating a string of asterisks at the very end of a trace as proof of a network outage, when it is very often a destination firewall silently blocking ICMP on the last hop while letting real application traffic (HTTP, etc.) through perfectly normally - it is worth cross-checking with a direct application-level test rather than jumping to conclusions about an outage. Another trap: running two traceroutes at different times, or from different starting points, can produce completely different paths because of asymmetric routing and load balancing across the internet - a perfectly normal network behavior, not an anomaly in itself.
When to use it
Pinpointing exactly where, on a full network path, a routing or latency problem actually shows up, instead of guessing. Working out whether a slowdown reported by a client originates in your own infrastructure, the ISP's network, or the destination network itself - an important distinction for knowing who to contact. Validating the path actually taken after a peering configuration change, a VPN tunnel, or a BGP announcement, to confirm traffic really is flowing through the expected route. Documenting an abnormal network path with concrete evidence in an incident report for a client or a vendor, rather than relying on an unsupported claim.
DNS Lookup (Nslookup)
Query DNS records: A, AAAA, MX, TXT, NS, CNAME, SOA, PTR, SRV, CAA.
Enter a domain, choose a record type (A, AAAA, MX, TXT, NS, CNAME, SOA, PTR, SRV, or CAA), then look it up.
Whois
Look up registration information for a domain or IP address.
Enter a domain or IP address to look up its registration details — registrar, owner organization, and important dates.
Blacklist Check
Check whether an IP address or domain is listed on public spam/abuse blocklists (DNSBL).
Enter an IPv4 address or domain and run it to check 7 public DNSBL/RBL blocklists at once - each shows as listed, not listed, or check failed.
TCP Port Scan
Check whether TCP ports are open on a host or IP: common ports, a custom list, or the full 1-65535 range.
Enter a host or IP, pick common ports, a custom list, or the full range, then scan to see which TCP ports respond.
A full range scan can take up to ~100 seconds. Large scans (more than 100 ports, including custom ranges/lists) are limited to 1 per minute per visitor.
Open ports (0)
HTTP Header Inspector
Fetch the HTTP response status and headers for a URL.
Enter a URL to fetch its HTTP response status code and every response header the server sends back.
SSL / TLS Certificate Checker
Inspect a host's TLS certificate: issuer, validity dates, and days remaining.
Enter a hostname to inspect its TLS certificate — issuer, validity dates, and days remaining before it expires.
Geo-IP Lookup
Look up the geographic location and network info for an IP address. Leave empty to look up your own public IP.
Enter any IP address, or leave it empty to look up your own, to see its approximate location and network/ISP info.
Subnet / CIDR Calculator
Computed entirely in your browser — no data sent to the server.
Enter an IP address and CIDR prefix (e.g. 192.168.1.0/24) to instantly compute the network range, broadcast address, and usable host count.
Speed Test
Basic download/upload throughput test against this server (accuracy depends on the server's own uplink).
Press Start to measure download and upload throughput against this server. Accuracy depends on this server's own connection.
Country Code Dictionary
ISO 3166-1 alpha-2 country codes — searched entirely in your browser.
Search or browse the list of ISO 3166-1 alpha-2 country codes, looked up entirely in your browser.
| Country | ISO Code |
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Phone Dialing Code Dictionary
International calling codes by country — searched entirely in your browser.
Search or browse international calling codes by country, looked up entirely in your browser.
| Country | Dial Code |
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World Clock
Pick a time zone to see the current time — drag the globe to spin it.
Pick a time zone from the list, or drag the globe, to see the current time there.
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Drag to rotate the globe.
French Mobile Network Status
Mobile antenna sites down or under maintenance in France, by operator (Orange, Free, SFR, Bouygues Telecom), from ARCEP's public data. Snapshot updated once a day by ARCEP - not a minute-by-minute feed.
Browse mobile antenna and fibre outage data by French operator — no input needed, updated automatically from ARCEP's public data.
Most affected departments
Number of sites currently down or under maintenance, by department. Click an operator above to filter.
Data: Arcep — Sites indisponibles · Official network status map
Fixed Network (Fibre)
Fibre (FTTH) network quality by operator: reported-outage rate and connection-failure rate, from ARCEP's public data. Monthly indicators, 6-month rolling average - not a live feed like the mobile section.
By operator (parent group)
Averages over the last 6 available months, per infrastructure-operator parent group.