A colleague says the shop is offline, a customer reports a blank page, or your own browser times out. Before you restart anything, you need one answer: is the website down for everyone, or only for you? The two have completely different fixes. A real outage is a server problem; a local failure is DNS caching, a VPN, a corporate proxy or your ISP.
The Is It Down check requests the website from the NetTools.tech server, outside your network, and returns a clear verdict together with the redirect hops, the final HTTP status, the total time and the server IP that answered. It takes a few seconds and needs nothing but the domain name.
What is an "is it down" check?
In simple terms
It is a second opinion from somewhere else on the internet. Our server tries to open the website just as a browser would. If our server gets an answer and you do not, the website itself is fine and the problem is between you and it.
Technical background
Loading a website involves several independent steps, and any of them can fail:
- DNS resolution – the domain name is translated to an IP address. Failures: expired domain, broken or missing records, an unreachable authoritative name server, or stale cached answers on your side.
- TCP connection – a connection to port 443 (HTTPS) is opened. Failures: server down, firewall dropping packets, routing problems, refused connections.
- TLS handshake – the server presents a certificate that must be valid for the hostname. Failures: expired certificate, wrong hostname, incomplete chain.
- HTTP request – the server answers with a status code (RFC 9110). 2xx and 3xx are normal, 4xx means the request was refused or the page does not exist, and 5xx means the server or an upstream application failed.
"Down" can mean any of these. The check tells you which step failed from our location, which narrows the search considerably.
Why use Is It Down?
- Separate local problems from outages. If the site answers from our server, you can stop debugging the web server and look at your own network.
- Avoid unnecessary escalations. Hosting support asks "is it down for everyone?" first; you can answer with a status code and a timestamp.
- Identify the failing layer. A DNS error, a refused connection, a certificate error and a 503 point to different teams.
- Check third-party services. When a SaaS login page or a payment provider fails, a quick outside check shows whether the problem is theirs.
Who should use it?
- Anyone who cannot open a website and wants to know whether waiting or troubleshooting locally makes sense.
- Helpdesk and support staff triaging "the site is down" tickets.
- Website owners and administrators who want an outside confirmation after a deployment or a DNS change.
- Network engineers ruling out the web server before looking at firewalls, VPNs or routing.
How the Is It Down check works
When you enter a domain, the check builds the URL https://<domain>/ and sends it to the NetTools.tech server, which handles it the same way as the HTTP Status checker:
- Input validation. Only a fully qualified public domain name is accepted. IP addresses, internal names such as
.localand invalid labels are rejected; internationalized domain names are converted to their ASCII (punycode) form. - DNS and destination guard. The server resolves the name. If resolution fails, the result reports that the domain could not be resolved. If any address is private, loopback, link-local or reserved, the request is refused. The connection is then pinned to the checked address.
- Request. A
GETrequest with the identified user agentNetToolsBot/1.0and no cookies, with a 10-second limit per request. TLS certificates are verified. - Redirects. 301, 302, 303, 307 and 308 redirects are followed manually, up to 10, and every target is checked again before it is requested.
- Verdict. If the final response has a status below 500, the site is reported as up. A status of 500 or higher is reported as a server error. If no HTTP response arrived at all, the site did not answer, and the error of the last hop is shown (DNS, timeout, connection or TLS).
The check runs once, from one location, within about 25 seconds overall. Per-client rate limits apply.
How to use the NetTools.tech Is It Down check
- Open Is It Down.
- Type the bare domain in the Domain field, for example
example.comorwww.example.com. Do not addhttps://or a path; the check always requests the home page over HTTPS. - Press Run Is It Down (or click the example chip).
- Read the colored status line first: up, server error, or did not answer.
- Look at the hop table to see where redirects led and which request failed.
- Use Copy if you want to paste the result into a ticket.
In the terminal the same check is /isitdown example.com (alias /down).
Understanding the results
| Result | Meaning | What to look for |
|---|---|---|
| "is up from the NetTools server (HTTP 200, 180 ms)" | The final response had a status below 500 | If you still cannot open the site, the problem is local or regional |
| "answers with a server error (HTTP 503)" | The server responded, but with a 5xx code | The web server runs, but the application, upstream or proxy behind it fails |
| "did not answer from the NetTools server: …" | No HTTP response at all | The message names the cause: DNS, timeout, refused connection or TLS/certificate error |
| Hop table: URL | Each URL requested, starting with https://<domain>/ | Redirects to another host, to http://, or to a login page |
| Hop table: Status | Status code and reason, or the error text | Where in the chain the failure happened |
| Hop table: Time | Duration of each request | One very slow hop can explain timeouts in browsers |
| Final status | Status of the last response | 4xx on the home page is unusual and worth checking |
| Total time | Duration of the whole check | Several seconds for a home page suggests an overloaded server |
| Server IP | Address that sent the final response | Whether DNS points where you expect (origin, CDN, new hosting) |
The note under the result is a reminder that the verdict comes from one location: a site can be up from our server and still unreachable from your network.
Example: up for us, down for you
A user reports that shop.example.com times out. The check returns:
shop.example.com is up from the NetTools server (HTTP 200, 212 ms).
Hop URL Status Time
1 https://shop.example.com/ 200 OK 212 ms
Final status 200 OK
Total time 212 ms
Server IP 198.51.100.20The server answers normally from outside. Next steps on the user's side: compare the IP their computer resolves (nslookup shop.example.com 1.1.1.1 versus their default resolver), flush the local DNS cache, try without VPN or proxy, and test from a mobile network. If their resolver returns an old address after a hosting move, DNS Propagation shows which resolvers still have the old record.
Common use cases
- Triage of outage reports: decide within seconds whether to page the on-call engineer or help the user locally.
- After DNS or hosting changes: confirm that the domain resolves and serves the site from the new IP.
- Certificate renewals: a failed renewal shows up immediately as a TLS error.
- Vendor status checks: confirm that a supplier's portal really fails before opening a ticket.
Troubleshooting
"The domain … could not be resolved"
There is no usable DNS answer. Check the A/AAAA records with DNS Lookup and the registration status with WHOIS. Expired domains and deleted records both look like this.
"No answer within 10 s" or a timeout
The server or a firewall did not respond. Test reachability with Ping (many servers do not answer ping, so a failure there is not conclusive), check port 443 with Port Check and look for where packets stop with Traceroute.
"Connection failed (ECONNREFUSED)"
The host is reachable but nothing listens on port 443. Either the web server is stopped or the site only offers plain HTTP. Try http:// with the HTTP Status checker.
"TLS/certificate error"
Visitors get a browser warning as well. Check expiry, hostname and chain with the SSL Certificate Checker.
Up from NetTools, down for you
Flush your DNS cache, try another resolver such as 1.1.1.1 or 9.9.9.9, disable VPN, proxy and browser extensions, and test from a different network. If only some regions fail, the cause may be a CDN, anycast or geo-blocking issue that one location cannot see.
HTTP 403 or 429 reported as up
The server answered but refused our request, often because of bot protection or rate limits. The site is running; whether real visitors are blocked too needs a browser check.
Common mistakes
- Entering a full URL. The Domain field expects
example.com, nothttps://example.com/page. For a specific URL, use HTTP Status. - Reading "up" as "working". A 404 or 403 home page counts as up because the server answered; the page itself may still be broken.
- Concluding "down for everyone" from one failed check. A timeout from our server can be a regional routing issue or a block of our IP range.
- Forgetting the
wwwvariant.example.comandwww.example.comcan point to different servers; check both. - Testing too often. Repeated checks within seconds hit rate limits and add nothing; give changes time to take effect.
Limitations
- One location, one moment. The result does not show regional outages, intermittent failures or problems that occur only under load.
- Only
https://<domain>/is tested; sites that serve only HTTP, or only specific paths, need the HTTP Status checker. - The verdict is based on the HTTP status class. It does not check page content, so a 200 error page or an empty page counts as up.
- IPv4 is used when a domain has IPv4 addresses, so IPv6-only problems are not detected.
- Sites that block automated or data-center traffic may answer with 403 or time out even though browsers work.
- It is not uptime monitoring: there is no history, no repeated testing and no alerting.
Security & privacy
The domain you enter is sent to the NetTools.tech server, which requests the home page and returns the result. The domain and the response are not stored. The target website sees a request from our server's IP address with the NetToolsBot user agent, not your IP address. Response cookies are not shown. Only public domains are contacted; private and reserved addresses are blocked.
Related tools
- HTTP Status – the same request for any full URL, with all response headers (guide).
- DNS Lookup – check the records a domain resolves to (guide).
- Ping and Traceroute – reachability and the network path (Ping guide, Traceroute guide).
- DNS Propagation – compare answers from many public resolvers after a change (guide).
- SSL Certificate Checker – diagnose TLS errors (guide).
Summary
Is It Down requests https://<domain>/ from the NetTools.tech server and reports whether an HTTP answer arrived, which status it had and where the chain failed if it did not. Up from our server but down for you points to DNS, network or device issues on your side; a DNS, connection, TLS or 5xx failure from our server points to the website. Treat it as a quick outside opinion, not as monitoring.
Frequently asked questions
How do I know if a website is down for everyone or just me?
Check it from a different network than your own. If the Is It Down check reaches the site from the NetTools.tech server but your browser cannot, the problem is most likely on your side, such as DNS caching, your ISP, a firewall, a VPN or a browser extension.
Why does the check say a site is up when it shows an error page?
The verdict is up for any HTTP status below 500, because the server answered. A 403 or 404 means the web server is running but refused or could not find the page, which is different from an outage.
Does Is It Down monitor a website continuously?
No. Each run is a single check at that moment from one location. For ongoing availability you need a monitoring system that checks repeatedly and alerts you.
Which URL does the check request?
It always requests https://<domain>/, the home page over HTTPS, and follows redirects from there. To test a specific path or plain HTTP, use the HTTP Status checker with a full URL.
Why does a site that only supports HTTP show as down?
The check starts with HTTPS on port 443. If the server does not accept HTTPS connections, the first request fails and there is no HTTP answer to report, so the site is reported as not answering.
Can I check an IP address or an internal server?
No. The input must be a public domain name, and domains that resolve to private, loopback or reserved addresses are refused. Internal systems cannot be reached from the NetTools.tech server anyway.