said by ancodia:if its that mission critical you can buy an external smtp service to use for less than $10 month.
Alternatively you should check out the Microsoft hosted services. For a couple bucks per month, per user you can have full spam filtering, webmail, virus scanning and inbound/outbound smtp. We use it & it's great.
Could you get me a link? $10 a month would be well worth it to avoid this mess ever again.
Thanks
Paul