WhenIP FAQ
Short answers to the questions people ask most often after checking an IP address or comparing probe results.
New to networking? Start with What is an IP address?, then compare what you saw from different probe locations if a result changed between San Francisco, New York, Amsterdam, or future probes.
What is my IP address?
Your public IP address is the address your connection presents to websites and services on the internet. WhenIP shows the address families our probes see when your browser reaches us.
Why do I see IPv4 but not IPv6?
Many networks still do not provide working IPv6. Some VPNs, privacy relays, mobile carriers, and router settings also disable or hide IPv6.
Why do results change when I switch probe locations?
Different probe locations can hit different routes, CDNs, firewalls, and DNS policies. That means ping, traceroute, port checks, and even the visible address family can vary by region.
When a result changes, compare the same tool from multiple probe locations before assuming something is broken everywhere.
Why can my IP address change?
Residential ISPs, mobile networks, VPNs, carrier-grade NAT, and failover paths can all change the public address that websites see.
Is IP geolocation exact?
No. IP geolocation is usually best for country, region, city-area, and timezone estimates. It is not a reliable way to determine a precise street address.
What does reverse DNS mean?
Reverse DNS is a PTR record that maps an IP address back to a hostname. Many residential addresses have no PTR at all.
Can this site scan any port on any target?
No. WhenIP intentionally limits active checks to a safe allowlist and to your own detected public address.
What does an open port mean?
It means a service accepted the connection on that port. It does not automatically mean the service is secure or intended to be public.
What does a closed port mean?
It means the target actively rejected the connection. Usually nothing is listening there or a host firewall rejected it.
What does filtered mean?
Filtered usually means the service did not clearly answer before timeout, often because of a firewall or network policy.
Why does ping fail when the internet still works?
Many networks or host firewalls block ICMP echo requests. A failed ping does not automatically mean the target is offline.
Why does traceroute show stars or timeouts?
Routers can rate limit or ignore traceroute probes even while forwarding traffic. Timeouts in the middle of a path are common.
Why does WHOIS sometimes look incomplete?
Modern registration privacy, TLD rules, rate limits, and registry policies can all reduce the detail returned by WHOIS.
What is the difference between DNS and reverse DNS?
Normal DNS maps hostnames to IP addresses. Reverse DNS maps IP addresses back to hostnames through PTR records.
Why does my VPN change what websites see?
A VPN forwards traffic through a different egress network. Websites see the VPN exit IP rather than your local ISP address.
Can WebRTC leak my IP?
Depending on browser settings and extensions, WebRTC can reveal local or public candidates to web pages. Some browsers now reduce that exposure.
What is a private IP range?
Private IPv4 ranges include 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. These are used inside local networks and are not publicly routed on the internet.
What is CIDR?
CIDR is notation that expresses how much of an address identifies the network, such as /24 for IPv4 or /64 for IPv6.
Why does mobile data look different from home internet?
Mobile carriers often use carrier-grade NAT, rotating IP pools, and centralized egress locations, so the public IP and geolocation can be very different from your device location.
Why do tools ask for a hostname instead of a full URL?
DNS and WHOIS tools operate on hostnames or domains. Including https:// paths or query strings makes the input invalid for those protocols.
What is WhenIP Academy?
It is the learning center for novice and pro users who want detailed explanations behind the results shown by the tools.