--On Friday, September 02, 2011 09:32 +1000 Mark Andrews
However, if a mail server is online for only a few hours a
day, then I'd seriously suggest getting a backup mail server
to accept messages during the downtime (or putting the main
mail server somewhere else with a better connection), unless
you don't really care about getting mail...
And poll when coming online using TURN after authenticating.
Also if you do this you should ensure that your backup MX can
reject non valid addresses or you will generate a lot of
backscatter. There are a number of different techniques that
can be used to do this.
That is one of several reasons why TURN was deprecated years ago.