What should we check?
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GuidesEvery CheckNet check has a guide: what it is, why it matters and how to fix it, step by step.My device
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Checks
More details
This connection
This device
This is what Cloudflare sees of this connection. Nothing is stored.
Your request headers
Speed test
Measured to the nearest Cloudflare data centre, with no other service involved. On a fast connection it uses up to about 200 MB of data.
Is it blocked?
The site is opened from networks inside the country and from outside it, next to OONI’s figures for the last month.
Does it open everywhere?
We open the site from several countries, so you can see whether it is reachable everywhere.
Port check
Timed from the Cloudflare data centre nearest to you, not from your device. Common ports only.
Ping and route
Ping tells you how far away a host is; traceroute and MTR show the path hop by hop. It runs from places around the world, not from your device.
DNS
Domain records, DNS and email health, and DNS answers from around the world.
DNS answers from around the world
Domain info
Registrar, registration and expiry dates and name servers, from RDAP.
SSL certificate
Check a site’s certificate, or read a certificate (PEM).
Have a certificate (PEM)?
IP lookup
The network owner, country, abuse contact and reverse name (PTR) of an IP.
Encode and decode
Everything runs in this browser; nothing you type here is sent anywhere.
The signature is not checked; only the contents are shown.
Subnet calculator
Type an IP with a prefix or a mask, like 192.168.1.10/24, or a number to turn into an IP.
Subnets and CIDR
The number after the slash, like 24 in 192.168.1.0/24, says how many leading bits of the address name the network; the rest are for devices. A /24 holds 256 addresses, 254 of them usable: the first is the network itself and the last is the broadcast.
A mask writes the same thing as an address: /24 is 255.255.255.0. Routers use it to tell whether an address is on the local network or has to be sent out.
Speed units
Providers sell megabits per second; browsers show downloads in megabytes.
Guides
Every CheckNet check has a guide: what it is, why it matters and how to fix it, step by step.