IPv6 isn't SMTP

Thu Mar 27 03:12:10 UTC 2014

On 3/26/2014 10:16 PM, Franck Martin wrote:
>
> and user at 2001:db8::1.25 with user at 192.0.2.1:25. 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.

From:
http://tools.ietf.org/html/rfc3986#section-3.2.2