Free guides and tutorials for DNS, SSL, networking, and web security.

Fix the 'DNS server is unavailable' error on Windows, Mac, and routers with 8 proven solutions — flush and renew DNS, switch to public resolvers, and repair the router's DNS forwarder.

Fix 'WiFi connected but no internet access' on Windows, Mac, Android, and iPhone — from DNS and IP renewal to router DHCP fixes, ordered from fastest to most thorough.

AT&T DNS server IP addresses (68.94.156.1 / 68.94.157.1), how DNS works on AT&T Fiber gateways like the BGW320, and faster alternatives like Cloudflare and Google DNS.

Fix the ERR_CONNECTION_REFUSED error in Chrome on Windows, Mac, Android, and iOS with 9 proven solutions — plus dedicated fixes for localhost and server owners.

Fix the ERR_NAME_NOT_RESOLVED error in Chrome on Windows, Mac, Android, and iOS with 9 proven solutions — from flushing DNS to fixing Secure DNS and Private DNS settings.

Comcast and Xfinity DNS server IP addresses (IPv4 & IPv6), how to change DNS on an xFi Gateway, and faster, more private alternatives like Cloudflare and Google DNS.

The 302 status code is a temporary HTTP redirect. Learn what HTTP 302 Found means, how it differs from 301/307/308, and how to send and debug it correctly.

Fix the DNS_PROBE_STARTED error in Chrome, Edge, and Brave. Learn what causes this DNS error, how it differs from NXDOMAIN, and 8 proven fixes for every OS.
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Fix the ERR_QUIC_PROTOCOL_ERROR in Chrome, Edge, and Opera. Learn what causes this QUIC protocol error and 7 proven methods to resolve it instantly.

Fix the "this network is blocking encrypted DNS traffic" warning on iPhone, iPad, and Mac. Learn what encrypted DNS means, why networks block it, and 7 proven solutions.

Complete list of Verizon Fios DNS server IPs by region, how to change DNS on your Verizon G3100 router, and why switching to Cloudflare or Google DNS speeds up your connection.

Get Spectrum's DNS server IP addresses (IPv4 & IPv6), learn how to change DNS on your Spectrum router, and discover faster alternatives like Google and Cloudflare DNS.