 Re: what exactly is "security server"
The simple way to think of them are as proxies (like a proxying firewall use). With the security servers very presice control of the protocol can be archived as well as additional security features, e.g. authentication of an ftp session by the firewall before the connection to the back-end ftp server is allowed.
As to where/when to use them, that a really open question. I would say the SMTP SS is probably used the most to do things like strip out attachments and scripts.
The SSes are also used by the embedded AV of the firewalls. |