# WHATPORT(4443)

## NAME

port 4443 — Alternate HTTPS (IANA: pharos) — The other alternate HTTPS port after 8443 — usually an appliance admin UI or a container that cannot bind 443.

Protocol: TCP  
IANA registry

## DESCRIPTION

IANA registers 4443 as pharos, but almost nothing you meet is that. The port survives as a convention: it is above 1024, so an unprivileged process can bind it, and it visually echoes 443, so vendors and container images pick it for a second TLS listener. Expect appliance and management consoles, secondary reverse-proxy endpoints, and sidecar services serving HTTPS to something else in the cluster. Whatever answers is a TLS server, so the certificate usually names the product for you.

## EXPOSURE

**Expose with care.** TLS is a floor, not a verdict: 4443 most often fronts an administrative UI, so treat it as an admin plane unless you have confirmed it is a public application endpoint.

## CHECK

```sh
openssl s_client -connect TARGET:4443 -servername TARGET </dev/null 2>/dev/null | openssl x509 -noout -subject -issuer
```

## SEE ALSO

- iana — [IANA port registry — 4443 (pharos)](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=4443) (iana.org)

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