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DFL-500 User Manual
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Firewall configuration
By default, the users on your internal network can connect through the DFL-500 NPG to the Internet. The
firewall blocks all other connections. The firewall is configured with a default policy that matches any
connection request received from the internal network and instructs the firewall to forward the connection to
the Internet.
Default policy
Policies are instructions used by the firewall to decide what to do with a connection request. When the firewall
receives a connection request in the form of a packet, it analyzes the packet to extract its source address,
destination address, and service (port number).
For the packet to be connected through the DFL-500 NPG, you must have added a policy that matches the
packet's source address, destination address, and service. The policy directs the action that the firewall
should perform on the packet. The action can be to allow the connection, deny the connection, require
authentication before the connection is allowed, or process the packet as an IPSec VPN packet.
You can enable and disable policies. You can add schedules to policies so that the firewall can process
connections differently depending on the time of day or the day of the week, month, or year. You can also
enable web content filtering for policies that control the HTTP service.
Use Int -> Ext policies to control how users on your internal network access the Internet. You can use these
policies to apply web content filtering to protect users on your internal network from downloading unwanted
content from the Internet. You can also use these policies to control IPSec VPN connections through the
firewall.
Use Ext -> Int policies to control connections from the Internet to your internal network. You can use these
policies to apply web content filtering. You can also use these policies to allow remote users to connect to
your internal network using PPTP and L2TP VPN.
This chapter describes:
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NAT/Route mode and Transparent mode
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Adding NAT/Route mode policies
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Adding Transparent mode policies
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Configuring policy lists
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Addresses
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Services
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Schedules
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Virtual IPs
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IP pools
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IP/MAC binding