How is ipv4only.arpa?

Be careful risk 20/100

Registered 13 years ago, on no blocklists we checked, no valid HTTPS certificate, the site did not answer (refusing to fetch internal address (192.0.0.171)).

Why

02050100

finecarefulhigh risk

+20No valid HTTPS certificate.

Rule-based: domain age, blocklists, TLS. A heuristic, not a guarantee.

Site

down

refusing to fetch internal address (192.0.0.171)

HTTPS

invalid

Host resolves to a private IP address

Age

13 years

registered 2013-09-30

Blocklists

listings across 5 lists

Everything we looked at

DNS records2 record types

A	192.0.0.171 192.0.0.170
NS	c.iana-servers.net b.iana-servers.net a.iana-servers.net ns.icann.org

Registrationregistrar not reported

registered	2013-09-30
nameservers	a.iana-servers.net b.iana-servers.net c.iana-servers.net ns.icann.org 199.4.138.53 2001:500:89::53

HTTPS certificatenot valid

valid	no
problem	Host resolves to a private IP address

DNSSECinsecure

Domain is not signed with DNSSEC

. → arpa → ipv4only.arpa

Email authenticationpoor

SPF	none
DMARC	none
DKIM	none of 1 common selectors

Whether mail claiming to be from this domain can be checked as genuine.

Security scoregrade C · 125/205

Basic Security

20/40missing: DNSSEC Enabled

Record Security

0/45missing: CAA Records, SPF Record, DMARC Record, DKIM Presence

Advanced Security

10/25missing: Mail Server Configuration, IPv6 Support

Domain Reputation

50/50

Threat Detection

45/45missing: Domain Age Check

Blocklists0 listings · 8 lookups

SURBL MultidomainURIBL MultidomainSpamCop192.0.0.170Barracuda192.0.0.170UCEPROTECT Level 1192.0.0.170SpamCop192.0.0.171Barracuda192.0.0.171UCEPROTECT Level 1192.0.0.171

Green: clean. Red: listed. Grey: the list did not answer.

Ask it yourself

Agents get this as data. Bought through the API, the checks behind this page cost $0.070: profile $0.025 + trust $0.020 + screenshot $0.020 + site status $0.005.

curl "https://how.is/v1/domain/trust?domain=ipv4only.arpa" \ -H "Authorization: Bearer $HOWIS_KEY" # or pay per call in USDC (x402), no key: the 402 tells your agent the price curl -i "https://how.is/v1/domain/profile?domain=ipv4only.arpa"

MCP: add https://how.is/mcp to Claude, Codex or Cursor (one-line install) and ask for domain_trust on ipv4only.arpa. Reference: /llms.txt.

Watch ipv4only.arpa. DNS read at the source every 5 minutes; certificate, blocklists and expiry every 6 hours. You get an email only when something changes.

Watch — $1 / 30 days