An IP address is like a building’s street address

Same public IP/port (443) → Nginx → different internal ports per app. 

• One IP, many services — An IP address is like a building’s street address. Ports are like apartment numbers. One building (IP) can have hundreds of apartments (ports), each holding a different service.

• Nginx’s job is to sit at the front door (ports 80 and 443) and figure out which tenant (subdomain) the visitor is asking for.

User -> https://fileman.sh1re.net  ---\
User -> https://transferdepot.sh1re.net -->  Nginx :443  --> routes by Host/SNI -->
User -> https://wiki.sh1re.net     ---/                                  |
                                                                          +--> fileman  -> 127.0.0.1:8083
                                                                          +--> depot    -> 127.0.0.1:8000
                                                                          +--> wiki     -> 127.0.0.1:3000

All three names → same public IP → Nginx routes by name to different upstreams/ports inside.

Gotchas to avoid

• Two server {} blocks that claim the same name: make sure server_name values don’t overlap unintentionally.

• Missing SNI/cert coverage: use a cert with SANs for all names or a wildcard *.sh1re.net.

• A “catch‑all” default_server can steal traffic if a name doesn’t match—verify with:

   curl -I -H "Host: transferdepot.sh1re.net" http://<IP>