Is x.224 specification freely available?

Question

I need to implement a simple probe that uses "open" microsoft rdp protocol. But that protocol refers to x.224 specification and ITU want money in order to download it. Is it any free version of x.224 protocol available?

Answer 1

While I was unable to find a free version of x.224 recommendation RFC1950 states this:

ITU-T Recommendation X.224, Annex D, "Checksum Algorithms,"
November, 1993, pp. 144, 145. (Available from gopher://info.itu.ch).
ITU-T X.244 is also the same as ISO 8073.

ISO 8073 is available on BANalyzer network protocol database.

Answer 2

X.244 is not a RDP Protocol, RDP is a MS protocol like ICA used by Citrix.

When you will perform a RDP connection, MS use this protocol to connect to the servers.

I took the sniffing when performing RDP to MS 2003 / 2008 to confirm the same.

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39 12:12:56 10.130.35.164 10.130.35.226 X.224 Connection Request (0xe0)

41 12:12:56 10.130.35.226 10.130.35.164 X.224 Connection Confirm (0xd0)

293 12:13:30 10.130.35.164 10.130.35.226 X.224 Connection Request (0xe0)

295 12:13:30 10.130.35.226 10.130.35.164 X.224 Connection Confirm (0xd0)

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Hope this helps..

Cheers!!

Dhruv

Answer 3

I downloaded the RDP spec doc from MS' Open Specifications site, and its reference to the X.224 standard contained a link to a page on the ITU web site that provides a PDF download.

Answer 4

I'm not sure if it was only recently released but you can find it here: http://www.itu.int/rec/T-REC-X.224-199511-I/en