The IInetLogInformation::GetSiteName method obtains the name of the server instance that is being logged.
virtual LPSTR STDMETHODCALLTYPE GetSiteName(
IN PCHAR pszSiteName,
IN PDWORD pcbSize
);
Logging modules should query for this method if a server instance has set the LogExtFileSiteName flag of the LogExtFileFlags metabase identifier.
LogExtFileSiteName, LogExtFileFlags