Resetting DTLS server

Michael Richardson mcr at
Tue Nov 12 07:53:27 UTC 2019

On 2019-11-12 7:38 a.m., Patrick Herbst wrote:
> If i setup a DTLS server, the client can connect once and send
> messages find.  but if the client restarts and tries to send data, the
> server hangs on SSL_read.

How are you handling the sockets on the server?
If you are creating a new 5-tuple [bind/connect] socket on the server
for each client, and the client then reuses it's socket, then it's
trying to speak the old instance on the server. 
> I'm assuming the server does not like a clienthello message when it is
> expecting application data.
> How can the server be made to recover and re-handshake with the
> restarted client?

Close the UDP socket on the client and open a new one to get a new
source port.
Does that work?  I'm not terribly happy with this solution, but it does
match what TCP would do.

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