Re: [BEHAVE] RFC6147 and RFC7208 interoperability issues

[Keith Moore <[e-mail]>]

On 2/6/22 19:58, Dan Wing wrote:

> A problem with rewriting SPF records within DNS64 is that other IPv4 addresses may well appear in TXT records, throwing a loop to applications which won't know if the DNS64 has done rewriting or if the application needs to do rewriting.  A long-standing problem with NAT "support" for applications since the days of FTP PASV.

+1

In general the problem with NATs is that they try to hide what they're 
doing from applications.   But they are never completely successful at 
that, and they cannot be.    And it's often difficult for the 
application to work-around the damage caused by the NAT.  In hindsight, 
it would have been far better for NATs to always be explicitly visible 
to applications; then at least the applications and NATs wouldn't be 
trying to second-guess one another.

But that's water under the bridge.   At this point the best thing that 
can be done is to transition to IPv6 only (except for some legacy 
hardware on local networks), and eradicate NATs as soon as possible.

Keith