IPv6 address literals probably aren't SMTP either

John Levine johnl at iecc.com
Thu Mar 27 03:28:28 UTC 2014

In article <5333970A.6070107 at direcpath.com> you write:
>On 3/26/2014 10:16 PM, Franck Martin wrote:
>> and user at 2001:db8::1.25 with user at Who had the good idea to use : for IPv6 addresses while this is the
>separator for the port in IPv4? A few MTA are confused by it.
>At the network level the IPv6 address is just a big number.  No 
>confusion there.  At the plaintext level the naked IPv6 address should 
>be wrapped in square brackets.

It's messier than that.  See RFC 5321 section 4.1.3.  I have no idea
whether anyone has actually implemented IPv6 address literals and if
so, how closely they followed the somewhat peculiar spec.


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