Fortinet FortiGate 1000A, Administration Manual

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01-28011-0254-20051115 Fortinet Inc.
About FortiGate Antivirus Firewalls Introduction
If an email message is found to be spam, the FortiGate unit adds an email tag to the
subject line of the email. The recipient can use their mail client software to filter
messages based on the email tag. Spam filtering can also be configured to delete
SMTP email messages identified as spam.
Firewall
The FortiGate ICSA-certified firewall protects your computer networks from Internet
threats. ICSA has granted FortiGate firewalls version 4.0 firewall certification,
providing assurance that FortiGate firewalls successfully screen and secure corporate
networks against a range of threats from public or other untrusted networks.
After basic installation of the FortiGate unit, the firewall allows users on the protected
network to access the Internet while blocking Internet access to internal networks.
You can configure the firewall to put controls on access to the Internet from the
protected networks and to allow controlled access to internal networks.
FortiGate policies include a range of options that:
• control all incoming and outgoing network traffic,
• control encrypted VPN traffic,
• apply antivirus protection and web content filtering,
• block or allow access for all policy options,
• control when individual policies are in effect,
• accept or deny traffic to and from individual addresses,
• control standard and user defined network services individually or in groups,
• require users to authenticate before gaining access,
• include traffic shaping to set access priorities and guarantee or limit bandwidth for
each policy,
• include logging to track connections for individual policies,
• include Network Address Translation (NAT) mode and Route mode policies,
• include mixed NAT and Route mode policies.
The FortiGate firewall can operate in NAT/Route mode or Transparent mode.
NAT/Route mode
In NAT/Route mode, the FortiGate unit is a Layer 3 device. This means that each of its
interfaces is associated with a different IP subnet and that it appears to other devices
as a router. This is how a firewall is normally deployed.
In NAT/Route mode, you can create NAT mode policies and Route mode policies.
• NAT mode policies use network address translation to hide the addresses in a
more secure network from users in a less secure network.
• Route mode policies accept or deny connections between networks without
performing address translation.