[gnutls-help] DTLS and gnutls_bye

Sean Greenslade sean at seangreenslade.com
Mon Feb 13 22:28:06 CET 2017

Hello, all. I've been writing a small server-client application that's
using GnuTLS's DTLS functionality. I must admit I'm not super familiar
with TLS in general, and it seems that DTLS is not used very often, so I
can't find too many examples of its use online.

My question is this: is gnutls_bye intended to be used with DTLS
"connections"? I realize that there isn't a proper connection in UDP,
but it seems like it would be useful to inform the other end of a
connection that there will be no further communications in this TLS

Specifically, the behavior I'm seeing is this. gnutls_bye does send the
close alert message over the wire, however the receiving end does not
raise an alert error when checking for received packets. I tested other
alerts, which go through and raise the proper alert error on the remote
end.  Also, after receiving the packet containing the close alert, the
remote end is still able to send packets back without error.

Is this a bug, or intended behavior?

Thanks for the help,


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