[Discuss] vz outgoing mail

[richard.pieri at gmail.com (Richard Pieri)]

On 10/1/2014 11:02 PM, Matthew Gillen wrote:
> (putting the localhost in square brackets to avoid MX resolution was a
> neat bit of arcana)

It's even more neat than that. One of the purposes (maybe the original
purpose?) is to use IP addresses in SMTP fields:

  define(`SMART_HOST', `[192.168.1.1]')dnl

It also works (should work, anyway) in mail address fields:

  To: discuss@[216.235.254.231]

for example. That will almost certainly cause all sorts of problems
since you're not getting MX processing and any filtering based on domain
part will probably fail, but it is a syntactically valid mailbox per RFC
2822.

-- 
Rich P.