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2.2.2 NNTP Server Messages

This section defines the creation of NNTP_AUTH_NTLM_Blob_Response messages. These NTLM messages are sent by the server and MUST be encapsulated as follows, in order to conform to syntax that is specified by the AUTHINFO GENERIC mechanism:

  1. Use base64 to encode the NTLM message data. Do this because NTLM messages contain data that is outside the ASCII character range, whereas NNTP supports only ASCII characters within the context of the AUTHINFO GENERIC command.

  2. Prefix the base64-encoded string that is obtained in step 1 with the NNTP response code string "381 " (the ASCII digits 3, 8, and 1 followed by the ASCII space character 0x20).

  3. Append the <CR> and <LF> characters (ASCII values 0x0D and 0x0A) to the resulting string as required by NNTP.

The ABNF definition of a server message is as follows:

 381 <base64-encoded-NTLM-message><CR><LF>

De-encapsulation of these messages by the client follows reverse logic:

  1. Remove the <CR> and <LF> characters (ASCII values 0x0D and 0x0A).

  2. Remove the NNTP response code string "381 " (the ASCII digits 3, 8, and 1 followed by the ASCII space character 0x20).

  3. Use base64 to decode the NNTP data in order to produce the original NTLM message data.