Port 8080: HTTP alternate
Port 8080 is the most common alternate port for web servers, admin panels and proxies.
What runs on port 8080
8080 became the go-to second HTTP port because it looks like 80 and, being above 1024, does not need administrator rights on Unix systems. Apache Tomcat, Jenkins and many Java applications default to it, and it is a traditional port for web proxies. It is usually plain HTTP, not encrypted.
On a home network
Routers often use 8080 for remote administration, and QNAP NAS devices serve their admin page on 8080 by default. IP cameras, DVRs and some smart-home hubs also use it for their web interface.
If port 8080 is reachable from the internet
If 8080 answers on your public address, a device's admin page is probably exposed, often without encryption. Exposed router and NAS panels are targeted constantly; the DeadBolt ransomware campaign in 2022 encrypted QNAP NAS boxes that were reachable from the internet. There is rarely a good reason for a home network to expose 8080; use a VPN or the vendor's cloud relay instead.
How to check whether it is open on your network
Look for 8080 in your router's remote management setting and port forwarding list, and check whether your NAS has UPnP port mapping switched on. RECON's Port Scan will show which LAN devices serve something on 8080.
To find out whether port 8080 is open on something in your home, and whether the internet can reach it, the app scans your Wi-Fi from your phone and checks your public address from the outside. It says what it checked and what it could not. Get RECON for iPhone — one-time purchase, no account, nothing leaves the device.