[dns-operations] [Ext] Nameserver responses from different IP than destination of request

[John Levine]

In article <20200908181130.GD4758 at straasha.imrryr.org> you write:
>> Seems to me that would be true for any software that uses the usual
>> BSD or linux socket calls that match the host and port ...

>You're conflating binding the UDP socket which specifies the *local end*
>of the UDP socket (and behaves as you describe) with the somewhat less
>common practice of "connecting" the UDP socket (done by DNS resolvers of
>various stripes) which then also limits the *remote peer* ...

Right, but I'd think that would be the usual way to do it. I suppose
the alternative is for each request, pick a port, do a send using that
port, then do a separate recv on the same port, but unless you're
actively trying to work around the wrong IP bug, why would you do
that?