dig ignores +notcp when doing IXFR (DiG 9.5.0-P2)

[Matthew Pounsett]

On 2013-12-06, at 12:11 , Chris Thompson <cet1 at cam.ac.uk> wrote:

> 
> The sense in which BIND "forces use of TCP" is that when it gets an
> IXFR request over UDP, it always just replies with the current SOA.
> It doesn't bother to work out whether an incremental transfer is
> possible and if so whether it would fit into the UDP payload.
> 
> Of course, if the client's supplied SOA serial is the same, this
> response indicates that no zone transfer is needed.

Yeah, the mechanism is clear.  I was curious about the why rather than the how.