Windows error 11001 (WSAHOST_NOT_FOUND): meaning and diagnosis

Status / error code:		Category:

Constant name:
Source:		Operating System:
Description: Name resolution received an authoritative indication that the requested host name does not exist.

Previous	Next
WSAEREFUSED	WSATRY_AGAIN

WSAHOST_NOT_FOUND

WSAHOST_NOT_FOUND is a resolver result, not a socket-connect result. In the legacy Winsock name-resolution APIs it means that an authoritative answer did not find the requested host. In DNS terms, the important distinction is between a name that does not exist and a temporary server or transport problem.

What to verify before retrying

Check the exact queried name after search-suffix expansion, spelling, IDN conversion, and configuration substitution. A retry without a changed name or DNS configuration usually cannot create a missing authoritative record. Negative answers can also be cached, so testing against a different resolver may produce the same result until the applicable negative-cache lifetime expires.

Useful troubleshooting

Query the intended FQDN directly and inspect the DNS response code and authority section.
Compare the application's resolver, system resolver, VPN/split-DNS policy, and hosts-file overrides.
Prefer GetAddrInfo for new code and log which name and record family were requested.

Microsoft: gethostbyname results · Microsoft: GetAddrInfo · IETF: DNS protocol · IETF: negative DNS caching

Looking for a different code? Search another status or error code.