Shortly we are planning to setup zimbra mail server (zimbra network edition) in the LAN on the ubuntu server. As of now we have hardware firewall fortegate 11c working as firewall but i do not know far this can control the antispam for the upcoming zimbra mail server in addition iam also aware zimbra is built with open source antispam can anybody please clarify the below doubts:
1. since we have hardware firewall fortegate 110c also zimbra has built in antispam feature, is it required to go for commercial anti spam solution if yes then please suggest economical and good product but iron port is too expensive for us to afford for.
2. If required antispam in addition to the hardware firewall fortegate 110c and built in antispam feature of zimbra please recommend good product with less budget as iron port is too expensive .
Thanks in advance.