TCP reply to UDP query (?) and NAT

[Jim Reid]

>>>>> "Oleg" == Oleg Tipisov <ovt at redcenter.ru> writes:

    Oleg> Is it allowed for the name server to return TCP reply to an
    Oleg> UDP query from another name server?

This makes no sense. Since there's no TCP connection established
between the client and server where would the server send any TCP
data? How would it know what port to send it to? And how would it know
the client was listening for a TCP connection request and willing to
establish a connection on that port?

    Oleg> For example, can this happen when local name server quries
    Oleg> root name server and the root name server returns a list of
    Oleg> other roots (NS and A RRs)? 

No.