The port you use when 8080 is taken — and Nexus Repository Manager's default.
IANA registers 8081 as sunproxyadmin, Sun's old proxy admin service, and Nmap still labels it blackice-icecap after a long-dead IDS console. Neither matters today: 8081 is the standard second HTTP port, and its most recognisable occupant is Sonatype Nexus Repository, whose documentation has you browse to http://localhost:8081/ after install. Artifact proxies, second app instances and container sidecars fill in the rest.
Expose with care
A Nexus instance on 8081 is an admin console plus your build artifacts, and it ships with a well-known default admin account that must be changed at first login. Public artifact mirroring can be deliberate; the console being public rarely is.
$ curl -sI http://TARGET:8081/Seen this on your network? Beige Box scans your Wi-Fi and shows every open port on every device — and its Ports tool links straight back here.
Get Beige Box →also available as JSON · Markdown
Corrections or a missing port? Reply @rimrocksystems.