# WHATPORT(7800)

## NAME

port 7800 — Apple Software Restore / JGroups cluster transport — IANA's Apple Software Restore port, and the default bind port for JGroups clustering under Infinispan, WildFly and Keycloak.

Protocol: TCP  
IANA registry

## DESCRIPTION

Two unrelated things answer here. IANA registers 7800 as asr, Apple Software Restore, the multicast disk-imaging service used to push macOS images across a lab network. Far more commonly on a server, 7800 is the JGroups TCP transport: Keycloak's documentation notes that for the embedded Infinispan cluster "by default, port 7800 is used" for unicast data between nodes, with failure detection at an offset of 50000 (57800). So an open 7800 on a Java application host usually means cluster members are talking to each other.

## EXPOSURE

**Do not expose.** JGroups cluster transport is not authenticated in a default configuration — a host that can reach it can attempt to join the cluster and read replicated cache contents, including sessions. Bind it to a private interface.

## CHECK

```sh
nc -vz TARGET 7800
```

## SEE ALSO

- docs — [Keycloak — Configuring distributed caches (JGroups bind port 7800)](https://www.keycloak.org/server/caching) (keycloak.org)
- iana — [IANA port registry — 7800 (asr)](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=7800) (iana.org)

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