What is the difference between a public and private IP address?
Private addresses are used inside the home; the router’s public address represents the connection on the internet. Under CGNAT even the router WAN may be private/shared.
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6 answers found · last checked 17 August 2026
Private addresses are used inside the home; the router’s public address represents the connection on the internet. Under CGNAT even the router WAN may be private/shared.
Most residential services use dynamic addresses that can change after lease/session/network events. Use supported DDNS or a paid static IP for a genuine requirement.
DNS translates names into IP addresses. If it fails, apps using cached/direct addresses may work while websites by name fail.
Only as a controlled diagnostic or informed policy choice. It may bypass provider filtering, alter privacy/performance and not fix weak Wi‑Fi.
Dual stack lets devices reach services over either protocol. IPv6 uses a different address format and is normal when supported.
Common causes are CGNAT/double NAT, wrong internal IP, local firewall, wrong protocol/port, or testing from inside without NAT loopback.