(moving here as not answered in Mail section)
Been using an SBS 2003 server on Business Broadband for years, with outgoing mail delivered (Exchange Server, SMTP) using relay.plus.net, but incoming mail delivered direct to port 25 (SBS 2003 has a good firewall, ISA). BTW had to change domain settings so that MX record points to mail.(ourdomain).co.uk.
However as SBS 2011 does not have ISA firewall, and everyone says an open port 25 can be vulnerable to attack, I think now is the time to stop having mail delivered directly, even though it has the advantage of almost instant delivery.
Anyone now of a good service to use which I can point our domain record at for mail delivery, and who will then relay it to our Exchange Server securely? (I assume that you can't use relay.plus.net for incoming email).
p.s. considering SpamHero at present