ZyXEL Communications VMG4325-B10A, User Manual

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Chapter 15 Firewall
VMG4380-B10A / VMG4325-B10A User’s Guide
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15.5 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 108
Security > Firewall > DoS
IP Type Select whether your IP type is IPv4 or IPv6.
Select Protocol Select the transport layer protocol that defines your customized port from the drop-down
list box. The specific protocol rule sets you add in the Security > Firewall > Service >
Add screen display in this list.
If you want to configure a customized protocol, select Specific Service.
Protocol This field is displayed only when you select Specific Protocol in Select Protocol.
Choose the IP port (TCP/UDP, TCP, UDP, ICMP, or ICMPv6) that defines your customized
port from the drop-down list box.
Custom Source
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 source.
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.
Apply Click Apply to save your changes.
Cancel Click Cancel to exit this screen without saving.
Table 79
Access Control: Add/Edit (continued)
LABEL DESCRIPTION