Sidewinder G2 6.1.2 Administration Guide - Glossary of Technical ...

Modifying the
interface
configuration
Chapter 3: General System Tasks
Modifying the interface configuration
2 The following settings may be enabled or disabled for each burb:
• Hide port unreachables—If this parameter is enabled, the Sidewinder
G2 will give no response if a node on the network attempts to connect to
a port on which the Sidewinder G2 is not listening. This increases
security by not divulging configuration information to potential hackers.
• Intra-burb packet forwarding—If enabled, traffic will be forwarded
between network interfaces located within this burb. Disabling this
parameter in a burb with two or more network interfaces has the effect
of separating the interfaces. This parameter should be disabled in burbs
with only one network interface.
Note: There is an interaction between the Intra-burb packet forwarding
parameter and NAT. NAT changes the source address of outbound packets
to the IP address of the Sidewinder G2 in the external (outgoing) burb. If
multiple interfaces exist in the same burb, that Sidewinder G2 has to select
an appropriate address based upon how it routes packets. By enabling this
option, the Sidewinder G2 must choose one of the interfaces for the source
address. In this case the Sidewinder G2 will always choose the address of
the first interface in the burb. Problems could occur if the destination is not
defined to use the same route back to the Sidewinder G2.
• Honor ICMP redirects—ICMP messages are used to optimize the
routes for getting IP traffic to the proper destination. On a trusted
network, honoring ICMP redirects can improve the throughput of the
system. On an untrusted network, ICMP redirects can be used by
hackers to examine, reroute, or steal network traffic. Enabling this
parameter allows the Sidewinder G2 to honor ICMP redirects.
• Respond to ICMP echo and timestamp—ICMP echo and timestamp
messages (also known as ping messages) are used to test addresses
on a network. The messages are a handy diagnostic tool, but can also
be used by hackers to probe for weaknesses. Enabling this parameter
allows the Sidewinder G2 to respond to these messages.
3 In the Internet burb drop-down list, specify which of the burbs defined on
the Sidewinder G2 is the Internet burb. The Internet burb is unique because
it is the only burb that communicates directly with the outside world.
4 Click the Save icon to save your changes.
The installation process defines Sidewinder G2’s internal and external network
interfaces. You can configure up to 64 interfaces, using a combination of
physical and VLAN interfaces. Using the Admin Console you can configure the
media type, the IP address, the subnet mask associated with an interface, and
the burb assigned to an interface. You can also enable hardware acceleration,
VLANs, DHCP, support for jumbo frames, and TCP checksum offloading.
To modify your interface configuration, start the Admin Console and select
Firewall Administration > Interface Configuration. The following window
appears.
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