Introduction
I recently faced a network configuration problem that initially looked simple:
How can I install V2Ray on a VPS when the only usable general-purpose public port is already occupied by qBittorrent?
The server was an Oracle Cloud Ubuntu VPS running qbittorrent-nox. Its WebUI was publicly accessible on TCP port 8080, while BitTorrent peer traffic used TCP and UDP port 47374.
Other candidate ports, including 80, 443, and 56894, were locally unused. However, external testing showed that they were not reachable through the Oracle Cloud network configuration. I did not want to modify the Oracle Virtual Cloud Network rules again, interrupt qBittorrent whenever I needed V2Ray, or expose unnecessary additional ports.
