Network diagnostics
Enter your hostname to see its current A / AAAA / CNAME records and compare them with the public IP 17NAS observes from your connection, so you know whether DDNS points to your current network.
The comparison uses 17NAS-observed connection information only. DNS resolution never connects to any address your hostname resolves to.
Detecting…Detecting…These are the public addresses 17NAS observes from your current connection: IPv4 when you reach this site over IPv4, IPv6 when you reach it over IPv6. They are used to compare against your DNS records.
You appear to be behind carrier-grade NAT (CGNAT), so the observed address is a shared address that DNS records cannot meaningfully match.
Enter a hostname to start
Depending on the result, continue troubleshooting your home network and remote access with these tools.
The tool looks up the current A, AAAA, and CNAME records of the hostname you enter and compares them with the public IPv4 / IPv6 that 17NAS observes from your connection. A match means your DDNS or DNS configuration currently points to the network you are on; a mismatch means the hostname still resolves to an older address. Observations come from 17NAS's single resolver and do not represent global DNS propagation.
A records point a hostname to an IPv4 address and AAAA records to an IPv6 address; a CNAME is an alias, and the address records of its target are what clients ultimately use. Home broadband usually gets a dynamic IPv4 address, so hostnames need DDNS updates. IPv6 addresses can differ from observed values due to privacy extensions or prefix changes, so treat IPv6 comparisons as indicative.
Once the hostname points to the right address, verify inbound access: the CGNAT Checker tells you whether you have a dedicated public IPv4, the Open Port Checker verifies that port forwarding actually works, and the IPv6 Test checks dual-stack connectivity. Together they cover the full NAS remote-access path.