How SlaySlop checks Block Lists

I still reach for dig when someone says a hostname is "blocked somewhere." Dig is fine for one resolver. It is a weak substitute for asking a whole class of blocking DNS servers and keeping the receipts. SlaySlop's DNS block lists check is the productized version of that habit.

Glossary definition first: the check "checks whether the domain or address appears on public block lists." About text: it "checks access to the URL using 10+ of the most popular privacy, malware and parental control blocking DNS servers." Related UI copy describes DNS blocklist resolver results for the domain, with blocklist, IP, and status columns, and a summary of blocked versus clear counts. Finding text can read "Listed on DNS blocklist."

That is the verified surface. I will not invent resolver brand names the marketing pages do not publish, or claim a score the catalog does not show.

Where the check sits

In the checks catalog, DNS block lists lives with reputation and threats: block lists, threat intel, and firewall detection. Security product pages describe public threat signals as part of the same broad pass that also looks at headers, TLS, and client-side secrets. Domain insights sits nearby for DNS and IP context when you need to see which address was implicated.

Scans remain read-only. You submit a public URL you own, manage, or have permission to test. Free teaser scans exist for public URLs; fuller report retention sits behind account and plan details on the pricing page. None of that turns a reputation check into a pentest.

What happens during the check

At a mechanical level the flow is:

1. Take the scan target URL and resolve the relevant domain or address context.
2. Ask the configured set of popular blocking DNS resolvers how they treat access to that target.
3. Record per-resolver outcomes plus the IP context the UI can show.
4. Summarize how many resolvers report blocked versus clear.
5. Attach that evidence to the finding so a later reader does not have to re-run folklore from memory.

I think of each resolver query as a narrow question: given your policy list, do you filter this name or address when someone asks for the URL? Privacy-oriented resolvers, malware-oriented resolvers, and parental-control resolvers answer that question for different reasons. The check aggregates those answers. It does not claim every recursive DNS server on the internet agrees.

# Evidence shape (illustrative)
{
  "check": "block-lists",
  "about": "10+ privacy, malware, parental-control DNS resolvers",
  "rows": [
    {"server": "resolver-family-a", "serverIp": "203.0.113.50", "status": "clear"},
    {"server": "resolver-family-b", "serverIp": "198.51.100.8", "status": "listed"}
  ],
  "summary": {"blocked": 1, "clear": 9}
}

How I read a result

Clear on the summary means the resolvers in the check set did not treat the target as listed at scan time. That is good handoff news. It is still a point in time. Shared IPs and fresh listings can change. Rescans and monitoring exist so you can see when public configuration or reputation shifts; I use that when a client had a listing last month and swears it is gone.

A listed row means at least one of those blocking DNS servers filtered the domain or address. Next questions stay practical:

• Is the listing on the apex name, a subdomain the campaign uses, or an IP your CDN neighbor also uses?
• Does dig from a normal resolver still return the real A/AAAA while the blocking resolver sinkholes it?
• Who owns remediation: DNS, hosting provider, or an abuse/listing appeal path?

# Permissioned troubleshooting sketch
dig example.com A +short
dig @9.9.9.9 example.com A +short
curl -sI "https://example.com/" | sed -n '1,12p'

Those commands are not the SlaySlop check. They are how I sanity-check a listed finding on a machine I control before I open a ticket. The report evidence remains the source of truth for what the product observed.

Boundaries I keep repeating

• Public resolvers, not private enterprise DNS you cannot see.
• Domain or address appearance on public block lists, not a full malware sandbox detonation.
• Read-only observation, not delisting work performed by SlaySlop on your behalf.
• One check among forty-five public checks; a clear reputation result does not clear security headers, availability, or SEO metadata.

Compare that with availability status for a second. Availability asks whether the public site responds and records its state. Block lists ask whether common blocking DNS policies filter the name or address. You can be up for the open internet and still filtered for users behind a parental-control resolver. You can be clear on block lists and still down on the probe URL. Different instruments.

Why keep the evidence next to the finding

Agency portals and PDF exports only help if the client sees the same rows you saw. SlaySlop's reporting product pitch is ranked findings with evidence, and shared portals without exposing the whole workspace. For block lists, that means the resolver result table travels with the finding. I want the client to see "listed" next to an IP and a status, not a vibes-based warning in an email.

Soft close: paste a URL you are allowed to test into SlaySlop, open the DNS block lists evidence, and read the blocked-versus-clear summary before you argue about whether the site is "on a list." The check is narrow on purpose. Use it that way.