- Category
- Original (1985 to 1988)
- IANA type
- Special Use
- Manager
- Internet Architecture Board (IAB)
- Script
- Latin
- DS in root
- 1 record(s)
- Algorithm
- 8 · RSASHA256
- Second-level
- 7 suffixes
- IDN names
- no IDN tables at IANA
- WHOIS
- whois.iana.org
- RDAP
- not in IANA's RDAP list
Checked 26 Oct 2026 by our weekly check.
Is a .arpa name registered?
Looked up from your browser in the registry's RDAP service; if that does not answer, in DNS. Nothing is stored on dnssec.in.What this means
The root zone holds a DS record for .arpa, so the extension is signed and anchored. A domain under .arpa can use DNSSEC with a full chain of trust: it needs to be signed at its DNS host and have its own DS at the registrar.
Second-level suffixes under .arpa (7)
You can register names directly under .arpa or under these suffixes, for example example.e164.arpa. Some are restricted to certain users (government, education, banks). Source: the Public Suffix List.
- .e164.arpa
- .home.arpa
- .in-addr.arpa
- .ip6.arpa
- .iris.arpa
- .uri.arpa
- .urn.arpa
IDN names under .arpa
No IDN tables for .arpa at IANA: names are usually ASCII only (a–z, 0–9 and hyphen).
Length
DNS limits are the same everywhere: each label is 1 to 63 characters, the whole name at most 253, letters, digits and hyphens, not starting or ending with a hyphen. IDN labels count their xn-- form, so fewer native characters fit. A registry can set a higher minimum (often 2 or 3 characters) or reserve short names: that is in its own policy.
WHOIS and RDAP
This extension is not in IANA's RDAP list. Classic WHOIS (port 43) answers at whois.iana.org. For most gTLD names the owner's contact details are redacted for privacy; the registrar, dates and status are public.
Lifecycle and drop
A restricted extension: who may register, and what happens at expiry, is set by its registry under its own rules, not by the usual ICANN registrar process.