Short references for the things the workbench calculates — and the things it cannot tell you.
01 / Networks
What /24 actually says
An IPv4 address contains 32 bits. A prefix such as /24 assigns the first 24 bits to the network, leaving 8 bits for addresses inside it: 2⁸ = 256 addresses.
For 192.168.1.80/24, the network starts at 192.168.1.0 and ends at 192.168.1.255. On a conventional subnet, .0 identifies the network and .255 is the broadcast address. Host addresses run from .1 to .254.
/31 is an exception used on point-to-point links, where both addresses can be endpoints. /32 identifies a single address. A calculator can describe a block; it cannot tell you whether a provider routes that block to you.
In https://example.org/docs?lang=en#start, example.org is the host, /docs is the path, lang=en is a query parameter and start is the fragment. The fragment is handled by the browser and is not included in the HTTP request to the server.
Percent encoding represents bytes with a percent sign and two hexadecimal digits. In form-style query strings, a plus sign represents a space. A literal plus can be written as %2B. Decoding is useful for reading values; it does not mean the address is trustworthy.
The same query key can appear several times. Do not assume that every server or application chooses the same value from repeated keys.
A ping reply shows that an ICMP exchange succeeded. A TCP connection shows that a particular port accepted a connection. An HTTPS response additionally involves TLS and the web application.
These are different tests. An ICMP reply does not establish that HTTPS works, and a failed ping does not establish that a web server is down. Record the destination, protocol, port, time and network used when comparing results.
Fieldnotes does not perform network probes. The tools on this site calculate and parse locally; they cannot measure reachability or certify a remote service.