[dns-operations] Resolver preference: Long TCP sessions vs repeated handshakes?

[Florian Weimer]

RFC 5966 section 5 suggests that concurrent TCP connections to resolvers 
should be avoided.

Due to architectural constraints, I have a choice between multiple 
parallel connections and long-term connections, or a new TCP connection 
for each query (which is closed after the response is received).

Which option is preferred by resolver operators?

This is about a special mode which uses TCP by default, which is 
activated by system administrators to work around issues with UDP packet 
delivery.  The default mode still tries UDP first.

Thanks,
Florian