What does errno 147 (EHOSTDOWN) in Solaris mean?

EHOSTDOWN

What EHOSTDOWN means on Solaris

EHOSTDOWN is Solaris errno 147, Host is down. It reports that the requested network operation cannot proceed because the destination host is considered unavailable. It does not mean that a connection “cannot be stopped,” and it is not a general description of client/server or peer-to-peer networking.

What to verify

• Record the exact socket or network call, destination address, route, and the errno immediately after the failing call.
• Check whether the host is reachable through the expected interface and route and whether neighboring network operations fail at the same time.
• Correlate the result with interface, routing, ARP/neighbor, gateway, and remote-host state before changing application protocol logic.

Recovery

Restore reachability to the destination host or select a valid route or endpoint, then retry according to the calling API's normal rules. A different errno such as connection refused or timed out identifies a different failure boundary and should not be collapsed into EHOSTDOWN.

References

• Oracle Solaris intro(2): error numbers
• illumos errno.h definitions
• POSIX errno.h