Using TFO with forward-addr, tls-upstream Resolvers

Jeff Hedley jeff.hedley at
Sun Feb 10 00:00:14 UTC 2019

Hello all,

Is tfo (TCP Fast Open) supposed to work with forward-zone, tls-upstream
servers? I see that tfo works when unbound attempts recursive (tcp) queries
itself, but when it uses a forward-addr for the query, tfo is not attempted.

I'm running unbound 1.9.0 configured with --enable-tfo-client and -server.
I confirmed the same behavior in version 1.8.3 as well.

Has anyone else successfully used tfo with a forward-addr tls upstream
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