Background: I am a SQL Server DBA. I have inherited about 50 SQL Servers and need to set up various maintenance plans and alerts. To get the full benefit, I'll also need to configure Database Mail to send emails when jobs fail, alert conditions occur, etc. This requires an SMTP server to relay email (hopefully I got the wording correct there). Since each SQL Server is on its own domain, it seems I will have to install the SMTP feature and configure on a server on each domain. I'm thinking I will do this directly on each SQL Server host.
I followed the step-by-step instructions in this MSDN article. Everything there made sense. After sidestepping a couple of anti-virus roadblocks, I've gotten email to flow through.
Question: What are the security ramifications of installing the SMTP feature? In my proof of concept, I configured SMTP to allow relays from 127.0.0.1 and no one else. Is this considered "secure". Are there other things I'm overlooking?
Update 08/21/2014: It turns out my company has existing access to a Microsoft SMTP server. It's a paid service, I'm told. I inferred from this that MS's SMTP server is not an open relay, per se. I connect to it via anonymous authentication, although I'm not sure how MS knows the sender is one of their paying customers (IP address, maybe?). So in the end, I have a single SMTP server, I don't have to maintain it, and I don't have to install and configure the SMTP feature on countless SQL Servers. Thanks, everyone for your input.