Symantec 10521146 - Network Security 7120 Administration Manual page 39

In blocking mode, all network traffic is examined by the Network Security
detection software before it enters your network, and is blocked if malicious.
When a protocol anomaly event or an event matching an enabled signature is
detected, the offending packet is dropped. For TCP/IP traffic, a reset is sent to
the TCP connection.
In alerting mode, the Network Security detection software still analyzes all
packets as they enter your network, but does not prevent an intrusion attempt
from proceeding. You can configure a non-blocking protection policy to send a
reset and an alert, based on event ID.
With only alerting enabled under in-line mode, there is no risk of inadvertently
blocking legitimate network traffic. The advantage of in-line alerting mode over
operating in passive mode is that you can enable blocking with a single
mouse-click from the Network Security console. You don't need to halt network
traffic while changing cabling and configuration to switch between in-line
alerting and blocking modes.
About fail-open
When you configure in-line mode on the Symantec Network Security 7100
Series appliance, you place the in-line interface pair directly into the network
path. If the appliance or one of those interfaces has a hardware or software
failure, all associated network traffic is blocked. You can avoid this risk with the
addition of the 2 In-line Bypass unit or 4 In-line Bypass unit, custom fail-open
devices available from Symantec specifically for the appliance. These devices
provide the fail-open capability, allowing your network to stay up while you
make repairs.
At this time, the bypass units are only available for copper interfaces. There is
currently no fail-open solution for the fiber interfaces of the appliance model
7161.
About management on the 7100 Series
The 7100 Series offers several management features in addition to those
provided by the Network Security software, as follows:
About the LCD panel
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About the serial console
■
About the compact flash
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About the LCD panel
The Symantec Network Security 7100 Series appliance is equipped with an LCD
screen and push buttons on the front bezel. The screen can display two lines of
About management and detection architecture
Architecture 39