ZyXEL Communications VMG8825-B Series, Руководство пользователя, Страница: 211 / 360

Chapter 18 Firewall
VMG8825-B Series User’s Guide
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18.5 The DoS Screen
DoS (Denial of Service) attacks can flood your Internet connection with invalid packets and connection
requests, using so much bandwidth and so many resources that Internet access becomes unavailable.
Use the DoS screen to activate protection against DoS attacks. Click Security > Firewall > DoS to display
the following screen.
Figure 122 Security > Firewall > DoS
The following table describes the labels in this screen.
Custom
Destination Port This field is displayed only when you select Specific Protocol in Select Protocol .
Enter a single port number or the range of port numbers of the destination.
Policy Use the drop-down list box to select whether to discard ( DROP ), deny and send an ICMP
destination-unreachable message to the sender of ( REJECT ) or allow the passage of ( ACCEPT )
packets that match this rule.
Direction Use the drop-down list box to select the direction of traffic to which this rule applies.
Enable Rate
Limit Select this check box to set a limit on the upstream/downstream transmission rate for the
specified protocol.
Specify how many packets per minute or second the transmission rate is.
Scheduler Rules Select a schedule rule for this ACL rule form the drop-down list box. You can configure a new
schedule rule by click
Add New Rule . This will bring you to the Security > Scheduler Rules screen.
OK Click OK to save your changes.
Cancel Click Cancel to exit this screen without saving.
Table 86 Access Control: Add/Edit (continued)
LABEL DESCRIPTION
Table 87 Security > Firewall > DoS
LABEL DESCRIPTION
DoS Protection
Blocking Select Enable to enable protection against DoS attacks.
Apply Click Apply to save your changes.
Cancel Click Cancel to exit this screen without saving.