Viewing the DoS sensor list, Configuring DoS sensors | Fortinet IPS

Viewing the DoS sensor list

DoS sensors

Viewing the DoS sensor list

To view the anomaly list, go to Intrusion Protection > DoS Sensor.

Figure 12: The DoS sensor list

Create New	Add a new DoS sensor to the bottom of the list.
ID	A unique identifier for each DoS sensor. The ID does not indicate the
	sequence in which the sensors examine network traffic.
Status	Select to enable the DoS sensor.
Name	The DoS sensor name.
Comments	An optional description of the DoS sensor.
Delete	Delete the DoS sensor.
Edit icon	Edit the following information: Action, Severity, and Threshold.
Insert DoS	Create a new DoS sensor before the current sensor.
Sensor before
icon
Move To icon	Move the current DoS sensor to another position in the list. After
	selecting this icon, enter the destination position in the window that
	appears, and select OK.

Configuring DoS sensors

Because an improperly configured DoS sensor can interfere with network traffic, no DoS sensors are present on a factory default FortiGate unit. You must create your own and then enable them before they will take effect. Thresholds for newly created sensors are preset with recommended values that you can adjust to meet the needs of your network.

Note: It is important to know normal and expected network traffic before changing the default anomaly thresholds. Setting the thresholds too low could cause false positives, and setting the thresholds too high could allow otherwise avoidable attacks.

To configure DoS sensors, go to Intrusion Protection > DoS Sensor. Select the Edit icon of an existing DoS sensor, or select Create New to create a new DoS sensor.

	FortiGate IPS User Guide Version 3.0 MR7
46	01-30007-0080-20080916

Image 46

Fortinet IPS Viewing the DoS sensor list, Configuring DoS sensors, Sequence in which the sensors examine network traffic

Contents

E R G U I D E Trademarks Contents DoS sensors Protocol decodersIPS sensors SYN flood attacks Introduction FortiGate IPS Document conventions About this documentFortinet documentation Typographic conventions FortiGate Pptp VPN User Guide Fortinet Knowledge Center Customer service and technical supportComments on Fortinet technical documentation IPS settings and controls IPS overview and general configurationThis section contains the following topics Default fail open setting When to use IPSDefault signature and anomaly settings Config ips global Set fail-open enable disable end Monitoring the network and dealing with attacks Setting the buffer sizeConfiguring logging and alert email Controlling sessions Attack log messages Signature Anomaly FortiGuard Center Adding protection profiles to firewall policies Using IPS sensors in a protection profileCreating a protection profile that uses IPS sensors Select Create New Adding protection profiles to user groups Using IPS sensors in a protection profile IPS predefined signatures Predefined signaturesViewing the predefined signature list Column SettingsEnable Clear All Filters Create a sensor and add IPS filters to it Viewing the predefined signature list IPS custom signatures Custom signaturesViewing the custom signature list Adding custom signatures using the CLI Custom signature configurationAdding custom signatures using the web-based manager Command syntax pattern Custom signature fields Creating custom signaturesShows the valid characters for custom signature fields Name BufferOverflow Custom signature syntaxAttackid Srcport Content keywords Keyword and value Description Deprecated, see pattern and context keywords Pattern yahoo.com Pattern GETContext uri Context host RegexdelimismxAEGRU PcreRegex/mdelim Uri !uristr Protocol tcp IP header keywords Keyword and Value Description TCP header keywords Keyword and Value Description Tcpflags AP Tcpflags S,12 Icmp keywords Keyword and Value Usage UDP header keywords Keyword and Value DescriptionOther keywords Keyword and Value Description Example custom signatures Example 1 signature to block access to example.comSbid --name Block.example.com Sbid --name Block.example.com Sbid --name Block.SMTP.VRFY.CMD Example 2 signature to block the Smtp ‘vrfy’ commandSbid --name Block.SMTP.VRFY.CMD --pattern vrfy Creating custom signatures Protocol decoders Protocol decodersUpgrading the IPS protocol decoder list Viewing the protocol decoder list Protocol decoder list Protocols Protocol decoder names Port IPS sensors AlldefaultAlldefaultpass Viewing the IPS sensor list Protectclient Configuring IPS sensorsAdding an IPS sensor Protectemailserver IPS sensor attributes IPS sensor filters IPS sensor overrides Configuring filtersReset Delete and Edit Delete or edit the filter Icons Configuring pre-defined and custom overrides Application Exempt IP Source DoS sensors Sequence in which the sensors examine network traffic Configuring DoS sensorsViewing the DoS sensor list Appears, and select OK Name Enter or change the DoS sensor name Comments Anomaly configurationDoS sensor attributes Will appear in the DoS sensor list Understanding the anomalies Udpscan Anomaly Description TcpdstsessionUdpflood Udpsrcsession Understanding the anomalies SYN flood attacks What is a SYN flood attack?How SYN floods work FortiGate IPS Response to SYN flood attacks What is SYN threshold?What is SYN proxy? How IPS works to prevent SYN floods IPS operation before synflood threshold is reached Suggested settings for different network conditions Configuring SYN flood protectionConfigure the options for tcpsynflood Select OK How Icmp sweep attacks work What is an Icmp sweep?Icmp sweep attacks FortiGate IPS response to Icmp sweep attacks Predefined Icmp signatures Icmp sweep anomalies Configuring Icmp sweep protection Index FortiGate Version 3.0 MR7 IPS User Guide Technical support