Chapter 15 Firewall
VMG3312-T20A User’s Guide
199
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 112 Security > Firewall > DoS
The following table describes the labels in this screen.
Protocol This field is displayed only when you select Specific Service in the Select Service field.
Choose the transport layer protocol (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 Service in the Select Service field.
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 Service in the Select Service field.
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 Enable 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 82 Access Control: Add/Edit (continued)
LABEL DESCRIPTION
Table 83 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.
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