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4.1 NNTP Client Successfully Authenticates to an NNTP Server

This section illustrates the NTLM Authentication: NNTP Extension with an example scenario in which an NNTP client successfully authenticates to an NNTP server by using NTLM.

NNTP client authenticates to an NNTP server

Figure 4: NNTP client authenticates to an NNTP server

  1. The client sends an NNTP_AUTH_NTLM_Initiation_Command to the server. This command is defined in [RFC2980] section 3.1.3.

     AUTHINFO GENERIC NTLM
    
  2. The server sends the NNTP_NTLM_Supported_Response message, indicating that it can perform NTLM authentication.

     381 Protocol supported, proceed
    
  3. The client sends an NNTP_AUTH_NTLM_Blob_Command message that contains a base64-encoded NTLM NEGOTIATE_MESSAGE.

     AUTHINFO GENERIC TlRMTVNTUAABAAAAB7IIogcABwAvAAAABwAHACgAAAAFA
     SgKAAAAD0dQVUxMQTFSRURNT05E
    

    The contents of the NTLM message after base64 decoding are:

     0x00000000  4E 54 4C 4D 53 53 50 00 01 00 00 00 B7 82 08 E2   NTLMSSP.....7_.b
     0x00000010  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
     0x00000020  05 02 CE 0E 00 00 00 0F                           ..N.....
      
    
  4. The server sends an NNTP_AUTH_NTLM_Blob_Response message that contains a base64-encoded NTLM CHALLENGE_MESSAGE.

     381 TlRMTVNTUAACAAAAFgAWADgAAAA1goriFuADDG03d7EAAAAAAAAAAGwAbABOAAA
     ABQLODgAAAA9FAFgAQwBIAC0AQwBMAEkALQA2ADYAAgAWAEUAWABDAEgALQBDAEwASQ 
     AtADYANgABABYARQBYAEMASAAtAEMATABJAC0ANgA2AAQAFgBlAHgAYwBoAC0AYwBsA
     GkALQA2ADYAAwAWAGUAeABjAGgALQBjAGwAaQAtADYANgAAAAAA
      
    

    The contents of the NTLM message after base64 decoding is:

      
     0x00000000  4E 54 4C 4D 53 53 50 00 02 00 00 00 16 00 16 00   NTLMSSP.........
     0x00000010  38 00 00 00 35 82 8A E2 16 E0 03 0C 6D 37 77 B1   8...5_b.`..m7w1
     0x00000020  00 00 00 00 00 00 00 00 6C 00 6C 00 4E 00 00 00   ........l.l.N...
     0x00000030  05 02 CE 0E 00 00 00 0F 45 00 58 00 43 00 48 00   ..N.....E.X.C.H.
     0x00000040  2D 00 43 00 4C 00 49 00 2D 00 36 00 36 00 02 00   -.C.L.I.-.6.6...
     0x00000050  16 00 45 00 58 00 43 00 48 00 2D 00 43 00 4C 00   ..E.X.C.H.-.C.L.
     0x00000060  49 00 2D 00 36 00 36 00 01 00 16 00 45 00 58 00   I.-.6.6.....E.X.
     0x00000070  43 00 48 00 2D 00 43 00 4C 00 49 00 2D 00 36 00   C.H.-.C.L.I.-.6.
     0x00000080  36 00 04 00 16 00 65 00 78 00 63 00 68 00 2D 00   6.....e.x.c.h.-.
     0x00000090  63 00 6C 00 69 00 2D 00 36 00 36 00 03 00 16 00   c.l.i.-.6.6.....
     0x000000A0  65 00 78 00 63 00 68 00 2D 00 63 00 6C 00 69 00   e.x.c.h.-.c.l.i.
     0x000000B0  2D 00 36 00 36 00 00 00 00 00   -.6.6.....
      
    
  5. The client sends an NNTP_AUTH_NTLM_Blob_Command message that contains a base64-encoded NTLM AUTHENTICATE_MESSAGE.

     AUTHINFO GENERIC TlRMTVNTUAADAAAAGAAYAHwAAAAYABgAlAAAABYAFgBIAAAACA
     AIAF4AAAAWABYAZgAAABAAEACsAAAANYKI4gUCzg4AAAAPZQB4AGMAaAAtAGMAbABpA
     C0ANgA2AHQAZQBzAHQARQBYAEMASAAtAEMATABJAC0ANgA2ANIo75EIhJe6AAAAAAAA
     AAAAAAAAAAAAAMhyv9JNozcmNID+tIH3fL2M2EXYMshTz9RZZq2XG5CpiugFZJWZKxk
     =
      
    

    The contents of the NTLM message after base64 decoding are:

      
     0x00000000  4E 54 4C 4D 53 53 50 00 03 00 00 00 18 00 18 00   NTLMSSP.........
     0x00000010  7C 00 00 00 18 00 18 00 94 00 00 00 16 00 16 00   |......._.......
     0x00000020  48 00 00 00 08 00 08 00 5E 00 00 00 16 00 16 00   H.......^.......
     0x00000030  66 00 00 00 10 00 10 00 AC 00 00 00 35 82 88 E2   f.......,...5__b
     0x00000040  05 02 CE 0E 00 00 00 0F 65 00 78 00 63 00 68 00   ..N.....e.x.c.h.
     0x00000050  2D 00 63 00 6C 00 69 00 2D 00 36 00 36 00 74 00   -.c.l.i.-.6.6.t.
     0x00000060  65 00 73 00 74 00 45 00 58 00 43 00 48 00 2D 00   e.s.t.E.X.C.H.-.
     0x00000070  43 00 4C 00 49 00 2D 00 36 00 36 00 D2 28 EF 91   C.L.I.-.6.6.R(o_
     0x00000080  08 84 97 BA 00 00 00 00 00 00 00 00 00 00 00 00   .__:............
     0x00000090  00 00 00 00 C8 72 BF D2 4D A3 37 26 34 80 FE B4   ....Hr?RM#7&4
      
    
  6. The server sends an NNTP_AUTH_NTLM_Succeeded_Response message.

     281 Authentication ok