Reaching Your Server

On your own network the server always works. Whether the wider internet can reach it depends on your connection; NAS Reborn finds out by probing your server from outside and shows you the result.

At home: always

Every device on your network can use the server: the network drive in Finder, Files and Windows, browsers, computers running rclone. The server announces itself on the local network, and its hostname resolves to its local address, the same URL as from outside, valid HTTPS included.

From the internet: the ladder

To accept visitors from outside, something must allow inbound connections through your router. NAS Reborn tries each rung in order and verifies the result from the outside:

IPv6. Many home connections have it, and there is no address sharing to fight; often it just works, though some routers block inbound IPv6 by default and need a firewall setting.
Automatic port mapping. The app asks your router to open a port, speaking both NAT-PMP/PCP and UPnP so most home routers are covered, and keeps the mapping alive while serving. Nothing to configure when it works.
Manual port forwarding. The reliable fallback on routers that support neither: forward external TCP port 443 to the address and port the app shows you. Router menus differ, but the app gives you exactly the values to enter and then verifies the result.

The Serve tab keeps score with a simple light: green when the outside probe reaches the server, yellow while checking, red when nothing works. Tapping it opens a live checklist showing each step, public address, DNS, the router's port mapping, and each port and address family probed, so a failure points at the rung that broke. When the router's admin page is detectable, the app links straight to it.

No false positives. The reachability probe makes a real connection from outside carrying a one-time token that only your device knows how to answer. An "open" port that is really answered by your router's own admin page does not count as reachable, and the app only ever offers addresses that have actually been verified to work.

When nothing gets through

Some providers, most mobile networks and a growing number of home ISPs, put customers behind carrier-grade NAT: your router never gets a public address of its own, and no setting can open a port on an address you don't have. If there is also no usable IPv6, unsolicited visitors cannot reach the device, and the reachability screen says so. It also warns when the device is serving over cellular data, where this is almost always the case.

What still works behind carrier-grade NAT:

everything on your own network, unchanged;
asking your ISP for a public IPv4 address or working IPv6, often a cheap or free option called "public IP" or "opt out of CGNAT";
a VPN overlay like Tailscale, installed on the server device and on the devices that need to reach it. The app's reachability screen offers this "skip the router" route directly, opening Tailscale or its App Store page.

There is deliberately no relay in the middle: no third party carries your traffic, meters your bandwidth, or can become a monthly fee.