I wanted my RocketRAID card and WSUS server to email me with any issues on my RAID array. I don’t run an email server, so I needed to find an SMTP service. I tried Gmail, but it only works if you can enable SSL, which you can’t with those devices.
It suggests port 2525 since some ISPs block outgoing port 25 for home accounts, but you can use ports 2525, 8025, 587 or 25 using the default SMTP settings they give. You can even use port 80 if your ISP really sucks by using SMTP server: port80.smtpcorp.com.