Re: [BEHAVE] RFC6147 and RFC7208 interoperability issues

[Keith Moore <[e-mail]>]

On 2/6/22 21:13, Christian Huitema wrote:

> Of course, doing that require special code in the SMTP server to 
> handle NAT64. But that's pretty much the only solution. 

Fortunately about the only consumers of SPF records are SMTP servers and 
spam filters.   And assuming that SPF is still in significant use (sigh) 
the developers of those products will be motivated to add support for 
SPF rewriting in the presence of NAT64.   It seems much better to put 
that optional/configurable fix in SMTP servers and spam filters than to 
burden every NAT64 with it.   Especially since the current trend seems 
to site SMTP servers for inbound mail "in the cloud" or at least in a 
rack somewhere completely outside the enterprise network, or even more 
likely, to outsource the inbound mail service entirely to somewhere that 
probably still has native IPv4 access should it be needed.    (And I 
suspect that trend will last longer than IPv4 does or NAT64 is needed.)

Keith