BinTec X4000, Руководство пользователя

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358 X4000 User’s Guide
Configuration of Security Functions and Firewall
10
10.4 Special Features
The following special features support your network security:
■
Startup Procedure ( chapter 10.4.1, page 358 )
■
Auto logout ( chapter 10.4.2, page 358 )
■
Prevention of Denial-of-Service Attacks ( chapter 10.4.3, page 358 )
10.4.1 Startup Procedure
X4000 does not start its routing activities until the complete configuration is
loaded, especially the defined filters. This means it is not possible to provoke a
system start to make use of an intermediate system state in which perhaps
routing takes place before the filters are active.
10.4.2 Auto Logout
Connections to X4000 via telnet,
➤➤
isdnlogin or serial interface are
disconnected automatically if no entry is made on the keyboard for a period of
15 minutes. This makes it difficult to read out or change the system
configuration on "forgotten" connections. You can change the time with the
command
t <time in seconds>
(see chapter 14.1, page 412 ).
10.4.3 Prevention of Denial-of-Service Attacks
A Denial-of-Service (DoS) attack is an attempt to flood a system or force a
restart by sending certain packets. This means the system or a certain service
can no longer be used.
Some Denial-of-Service attacks on the router itself are already prevented by the
internal coding.
For example, all X4000 interfaces for which you activate Network Address
Translation (NAT) protect the connected PCs against some DoS attacks with