On Tue, 21 Sep 2021, Bill Cole wrote:
On 2021-09-21 at 12:25:30 UTC-0400 (Tue, 21 Sep 2021 10:25:30 -0600)
Grant Taylor <gtay...@tnetconsulting.net>
is rumored to have said:
But why the penalty for using non-public addresses* in a Message-ID: string?
Empirical evidence. The use of a non-public address in a Message-ID correlates
to a message being spam. In my experience, so does using an IP literal of any
sort in a Message-ID, but that may be an idiosyncrasy in my mail.
I was not aware that Message-ID had any requirements that the content had to
mean anything beyond being syntactically correct. As such I would expect
private / non-globally routed content to be allowed. After all, isn't the
purpose of the Message-ID to be a universally unique identifier? If so, why
does it matter what the contents is as long as it's syntactically correct?
What am I missing?
Private IP addresses in general cannot specify globally unique devices
(consider 127.0.0.1 or the very-popular 192.168.1.1) and therefore a Message-ID
using an IP literal as the RHS part with a non-public IP cannot assure
uniqueness.
That is valid for Private IP addresses.
However "[IPv6::ffff:193.168.1.30]" is the representation of IPv4: 193.168.1.30
which is a Public IP address, thus that 'hit' is in error.
This should be considered a parsing bug.
--
Dave Funk University of Iowa
<dbfunk (at) engineering.uiowa.edu> College of Engineering
319/335-5751 FAX: 319/384-0549 1256 Seamans Center, 103 S Capitol St.
Sys_admin/Postmaster/cell_admin Iowa City, IA 52242-1527
#include <std_disclaimer.h>
Better is not better, 'standard' is better. B{
