User's Guide
50
GlobeSurfer
®
III User guide
Firewall
Your GlobeSurfer
®
III has a true firewall that uses rules to control the incoming
and outgoing data traffic. The firewall has three pre-defined levels of security.
The default, ‘typical security’, blocks traffic initiated by an external (Internet)
source, and allows traffic initiated from the local network.
Control the traffic
A firewall blocks uninvited Internet traffic that might cause damage to the com-
puters in your network. Before traffic is allowed in or out of your network, it has
to pass through the firewall. Incoming traffic is examined to see whether it meets
the conditions of incoming rules. If the conditions are met, the traffic is allowed
in. Outgoing traffic is also examined and compared to outgoing rules before it
is allowed out. Rules are based on Internet services, such as FTP, Telnet and
NetMeeting.
Is it necessary to change the default firewall rules or add new rules?
For private use, you should not have to add new rules or change the default rules.
By default, all incoming traffic is blocked and all outgoing traffic is allowed. If you
set up a virtual server, an additional incoming rule is automatically added to en-
able access to the server from the Internet.
An example of an attack that your GlobeSurfer
®
III will automatically block is a
DenialofService(DoS)attack.Thisisanattackwhereahackerchoosestoood
your network with more requests than it can handle. While this type of attack
would not harm computers in the network, it could slow or even stop network
operations. You do not need to set up a firewall rule for this.
More information about the firewall and applying corporate grade security is
provided in the ‘Reference Manual’.
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