· lpszAgent
Address of a string that contains the name of the application or entity calling the Internet functions (for example, Microsoft Internet Explorer). This name is used as the user agent in the HTTP protocol.

· dwAccessType
Type of access required. Can be one of these values:
INTERNET_OPEN_TYPE_DIRECT
Resolve all host names locally.
INTERNET_OPEN_TYPE_PROXY
Pass requests to the proxy unless a proxy bypass list is supplied and the name to be resolved bypasses the proxy. In this case, the function proceeds as for INTERNET_OPEN_TYPE_DIRECT.
INTERNET_OPEN_TYPE_PRECONFIG
Retrieve the proxy or direct configuration from the registry.

· lpszProxyName
Address of a string that contains the name of the proxy server (or servers) to use if proxy access was specified. If this parameter is NULL, the function reads proxy information from the registry. For more information about this parameter, see the comments below.

· lpszProxyBypass
Address of an optional list of host names or IP addresses, or both, that are known locally. Requests to these names are not routed through the proxy. The list can contain wildcards, such as "157.55.* *int*", meaning any IP address starting with 157.55, or any name containing the substring "int", will bypass the proxy.
If this parameter specifies the "<local>" macro as the only entry, the function bypasses any host name that does not contain a period. For example, "www.microsoft.com" would be routed to the proxy, whereas "internet" would not.
If this parameter is NULL, the function reads the bypass list from the registry.

· dwFlags
Flag that indicates various options affecting the behavior of the function. Can be a combination of these values:
INTERNET_FLAG_OFFLINE
Satisfy download operations on this handle through the persistent cache only. If the item does not exist in the cache, the function returns an appropriate error code.
INTERNET_FLAG_ASYNC
Future operations on this handle may fail with ERROR_IO_PENDING. A status callback will be made with INTERNET_STATUS_REQUEST_COMPLETE. This callback will be on a thread other than the one for the original request. A status callback routine must be registered or the functions will be completed synchronously.