RFC 5764, "Datagram Transport Layer Security (DTLS) Extension to Establish Keys for the Secure Real-time Transport Protocol (SRTP)", May 2010

Note: This RFC has been updated by RFC 7983, RFC 9443

Errata ID: 3913
Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT
Reported By: Martin Thomson
Date Reported: 2014-03-06
Held for Document Update by: Ben Campbell
Date Held: 2015-07-22

Section 5.1.2 says:

Arriving packets may be of types RTP, DTLS, or STUN [RFC5389].
...
                   |       B < 2   -+--> forward to STUN
...
If the value of this byte is 0 or 1, then the packet is STUN.

It should say:

Arriving packets may be of types RTP, DTLS, or STUN [RFC5389].  
STUN messages with methods identifiers of 1280 or higher cannot 
be demultiplexed.
...
                   |       B < 20  -+--> forward to STUN
...
If the value of this byte is less than 20, then the packet is STUN.

Notes:

This is a tricky one. We can't distinguish all STUN message types,
because - at least in theory - new message types >= 1280 can be added
to STUN, which could collide with DTLS.

Please see Section 7 of RFC 7983 for the change that addresses this problem more
holistically and *differently* than above.

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