Looking to find out infrastructure recommendations/hardware solutions/appliance solutions that can handle a fairly high volume of e-mail accounts and traffic.
There is a lot of cruft out there and marketing speak for hardware that looks way overpriced for what you get and at the same time there might be some great deals out there.
Quick spec. We have a need for hosting over 1500 domains and 8000 individual e-mail accounts (each with an average 3 aliases) and need to handle the POP/IMAP and SMTP. We also want to have some fairly advanced spam filtering and handling built into the inf. On average e-mail space usage doesn't go above 250mb. But some accounts will use 2-3GB.
We have our own datacenter and such, and up until recently have been using a third party hosting solution that tends to go down a lot lately and we are wanting to bring this "in-house" now. Just looking to see if there are any good directions I could be pointed for positive results you've had with e-mail solutions.