TL;DR: Use a random IP generator for examples, labs, and fake data you control. Do not use it to probe networks you do not own, to fill a proxy list, or to impersonate a person. Prefer addresses that cannot be confused with your company or your household, and say “example” in the same breath as the number. The page at the random IP tool will keep minting specimens. You decide whether the specimen stays on the lab bench.
A marketing blog almost named a stranger
A small hosting company published a tutorial on reading mail headers. The author clicked a generator, pasted the first address into a screenshot, and shipped the post on a Friday. On Monday a reader recognized the address as a small church’s mail server, because the reader volunteered there and had just been fighting a blocklist. The generator had not “attacked” the church. The blog had published a live address as if it were fiction, and other readers were now digging into it with tools that are not gentle. The company edited the post to a documentation-range address and wrote an apology that was longer than the tutorial. The policy they should have had was one sentence: do not publish a random draw you have not checked.
Allowed uses
Generate addresses for drafts that stay inside a team, for unit tests that mock a socket and never dial it, for classroom handouts that are about the shape of the number, and for lab firewalls on a network that cannot route to the public internet. Label them. “Example: 203.0.113.10” is a different sentence from a bare quad in a blocklist recommendation. If you are writing fiction or training data, keep a column called synthetic so nobody later imports the file into a production denylist.
- Do use documentation ranges when the audience is the public and the point is the format.
- Do regenerate if the draw collides with your own company’s addresses.
- Do throw lab rules away when the class ends.
- Do not scan, ping-sweep, or “just see who answers” on random public addresses.
- Do not sell or share a generated list as a proxy or VPN inventory.
The line between a lab and the internet
A virtual machine with its uplink disconnected can hold any address you like. You are rearranging a sandbox. The moment that VM can route, a “test” connection to a random address is a connection to whoever holds it. Ownership is the rule. If you cannot name the person who said you may send traffic there, you may not. Curiosity is not a ticket. A generator does not grant one.
Reserved and private ranges are safer in writeups because the rest of the internet agrees they are not a single public host. They are worse in a lesson that is specifically about public routing, unless you say you chose them because they are reserved. State the choice. Students copy what you do, not what you meant.
People’s faces are not in the number, until you add them
An address is not a name. It becomes personal when you attach a story: “this customer,” “this employee,” “this household.” Do not generate an address and then, for color, add a real city and a real company from memory. That combination is how a specimen turns into an implication. If the lesson needs a villain, invent the organization too.
Rate, volume, and courtesy
Clicking for a handful of examples is the intended pace. Hammering the page to build a million-row file is a burden on a free tool and a smell that the file is about to be used for something broader than a worksheet. If you need large synthetic sets, generate them on your own machine with a script that filters reserved space, and keep the file internal. Do not launder that script’s output through other people’s networks to “validate” it.
Also skip any workflow that asks you to paste the generated address into a complaint, a law-enforcement form, or an abuse desk as if it were an attacker you observed. False reports waste someone’s afternoon and can land on an innocent network. Report addresses you actually saw in a log you are responsible for.
Incident writeups need the log, not a stand-in
After a real event, the addresses in the report must be the ones the log recorded, handled under your disclosure rules. Swapping in a fresh random draw to “protect the attacker” also protects you from being accurate, and it can accuse a bystander who drew the same number later in a different context. Redact with your process: mask, summarize, or use a documentation address and say the real value is withheld. Do not quietly replace evidence with a new click.
One sentence to tape above the button
The hosting company’s apology was a policy written too late. Tape the short version above your own habit: specimens for documents and labs you control, never for contact with networks you do not. Generate freely inside that fence. Outside it, the button is the wrong tool, and checking an address after you have already published it is the expensive way to learn the fence was real.