IFWXSession::GetHostByAddr method

Article
08/27/2012

Applies to: desktop apps only

The GetHostByAddr method retrieves host information corresponding to an address.

Syntax

HRESULT GetHostByAddr(
  [in]       const char *addr,
  [in]       int len,
  [in]       int type,
  [out]      char *buf,
  [in, out]  int *buflen
);

Parameters

addr [in]
Pointer to the network address for the host. Host addresses are stored in network byte order.
len [in]
Length of the address.
type [in]
Type of the address.
buf [out]
Pointer to the data area to receive the hostent data. The data area must be larger than the size of a hostent structure because the supplied data area is used by Windows Sockets (Winsock) to contain a hostent structure and all of the data referenced by members of the hostent structure. A buffer of MAXGETHOSTSTRUCT bytes is recommended.
buflen [in, out]
On input, specifies the size of the data area for the buf parameter. If the buffer is too small, the error code HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER) is returned and the buflen parameter receives the size of the required buffer.

Return value

This method can return one of these values.

S_OK
The method was successful. The buffer was filled with the host information.
HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER)
Insufficient buffer space was provided. That is, the buffer pointed to by buf is not large enough to contain the host information.
HRESULT_FROM_WIN32(WSAHOST_NOT_FOUND)
The address specified could not be found in the relevant database.
HRESULT_FROM_WIN32(WSATRY_AGAIN)
No response was received from an authoritative server.
HRESULT_FROM_WIN32(WSANO_DATA)
The address specified is valid and was found in the database, but no information of the type requested is associated with it.

Remarks

Like the IFWXFirewall::GetHostByAddr method, this method checks permissions and policy rules, prior to providing the address. If there are no permissions or if the policy rules do not allow access, the host information will not be provided, and the method will return HRESULT_FROM_WIN32(WSAHOST_NOT_FOUND). This method also logs the name resolution and can use autodial to dial out for the name resolution.

Requirements

Minimum supported client	None supported
Minimum supported server	Windows Server 2008 R2, Windows Server 2008 with SP2 (64-bit only)
Version	Forefront Threat Management Gateway (TMG) 2010
Header	Wspfwext.idl
DLL	Wspsrv.exe

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