What are loopback, link-local and other special-purpose addresses?¶
Not every IP address represents a public internet connection or subscriber.
Recognise the common categories¶
| Address type | Typical meaning |
|---|---|
| 127.0.0.0/8 or ::1 | Loopback: communication within the same device |
| 169.254.0.0/16 or fe80::/10 | Link-local: communication on the local network link |
| 10/8, 172.16/12, 192.168/16 | Private addresses reused inside local networks |
A private address may identify an internal interface in a household, workplace or venue, but the external service will normally see a translated public address. The same private value can exist in countless unrelated networks.
Other reserved ranges support documentation, testing, multicast and network functions. Treat the address as a clue about the recording system’s context, not as an automatic provider lead.
Check the field¶
Establish which system recorded it and whether it was a source, destination, interface, gateway or placeholder. A special-purpose address is not necessarily an error; it may simply be meaningful only inside that network.
The point to remember
Special-purpose addresses can explain local system behaviour, but they cannot by themselves identify an external customer, device or person.
