Please, no Windows vs Mac vs Linux debates. There are already plenty of those around.
Do I have to be concerned about my Asterisk server getting a virus or some other kind of malware? Assuming it is behind NAT with only the required ports for SSH, FreePBX/FOP access from the internet, and of course, remote extensions. I’ve never heard of anyone having problems but if anyone has I’d like to know
VPN or public IP access lists are NOT an option.