Is Quad9 down today?

DNS queries not resolving at all

If domains stop resolving, first check that your system actually uses 9.9.9.9 or 149.112.112.112 as the resolver. Run ``nslookup example.com 9.9.9.9`` in your terminal — if it times out, the issue is upstream connectivity, not the service itself. Flush your local DNS cache: on Windows use ``ipconfig /flushdns``, on macOS ``sudo dscacheutil -flushcache && sudo killall -HUP mDNSResponder``.

A specific site is blocked unexpectedly

Quad9 filters domains associated with malware and phishing. If a legitimate site gets blocked, it''s likely caught by the threat intelligence feed. Try resolving through 9.9.9.10 — the unfiltered variant — to confirm the block. You can also submit a false-positive report via the official unblock request form at quad9.net.

High latency on DNS lookups

Slow resolution usually means your queries are routed to a distant anycast node. Check which node responds by running ``dig +short whoami.ds.akahelp.net @9.9.9.9``. If the latency stays above 80–100 ms, try switching to the IPv6 address 2620:fe::fe — sometimes it hits a closer PoP depending on your ISP routing.

Online banking or payment site won''t load

Some financial platforms use domains that overlap with blocklists. If your bank or payment gateway fails while other sites work fine, test with:

- nslookup bankdomain.com 9.9.9.9

- nslookup bankdomain.com 9.9.9.10

If the filtered resolver returns NXDOMAIN and the unfiltered one resolves correctly, the domain is being blocked. Use the unblock form or temporarily switch your resolver for troubleshooting.

DNS-over-HTTPS stops working in browser

Firefox and Chrome both support DoH natively. If it breaks after a browser update, go to network settings and re-enter the endpoint: ``​https://​dns.​quad9.​net/​dns-​query``. Some corporate firewalls block port 443 to external resolvers — in that case DoH will silently fall back to the system resolver without warning.

IPv6 resolution fails while IPv4 works

This usually points to a misconfigured IPv6 stack on the client side, not the resolver. Verify that 2620:fe::fe is reachable: ``ping6 2620:fe::fe``. If ping fails, check your router''s IPv6 settings and whether your ISP actually assigns a valid IPv6 prefix to your connection.