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                        USER GUIDE
FortiGate
IPS User Guide
Version 3.0 MR7
www.fortinet.com                                                                                                                                                                                                                                                                                                                                                                                                                                                
                    
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                        FortiGate IPS User Guide Version 3.0 MR7 September 16, 2008 01-30007-0080-20080916 © Copyright 2008 Fortinet, Inc. All rights reserved. No part of this  publication including text, examples, diagrams or illustrations may be  reproduced, transmitted, or translated in any form or by any means,  electronic, mechanical, manual, optical or otherwise, for any purpose,  without prior written permission of Fortinet, Inc. Trademarks Dynamic Threat Prevention System (DTPS), APSecure, FortiASIC,  FortiBIOS
                    
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                        Contents  Contents Introduction ........................................................................................ 5 The FortiGate IPS............................................................................................... 5 About this document......................................................................................... 6 Document conventions.................................................................................. 6 Fortinet documentation .......................
                    
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                        Creating custom signatures........................................................................... 23 Custom signature fields .............................................................................. 23 Custom signature syntax ............................................................................ 24 Example custom signatures........................................................................ 33 Protocol decoders ..................................................................
                    
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                        Introduction The FortiGate IPS Introduction This section introduces you to the FortiGate Intrusion Prevention System (IPS)  and the following topics: • The FortiGate IPS • About this document • Fortinet documentation • Customer service and technical support The FortiGate IPS Spam and viruses are not the only threats facing enterprises and small  businesses. Sophisticated, automated attack tools are prevalent on the Internet  today, making intrusion detection and prevention vital to securing corp
                    
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                        About this document Introduction About this document Document conventions The following document conventions are used in this guide: • In the examples, private IP addresses are used for both private and public IP  addresses. • Notes and Cautions are used to provide important information: Note: Highlights useful additional information.  Caution: Warns you about commands or procedures that could have unexpected or  ! undesirable results including loss of data or damage to equipment. Typographic co
                    
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                        Introduction Fortinet documentation • FortiGate Installation Guide Describes how to install a FortiGate unit. Includes a hardware reference,  default configuration information, installation procedures, connection  procedures, and basic configuration procedures. Choose the guide for your  product model number. • FortiGate Administration Guide Provides basic information about how to configure a FortiGate unit, including  how to define FortiGate protection profiles and firewall policies; how to app
                    
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                        Customer service and technical support Introduction Fortinet Knowledge Center  Additional Fortinet technical documentation is available from the Fortinet  Knowledge Center. The knowledge center contains troubleshooting and how-to  articles, FAQs, technical notes, and more. Visit the Fortinet Knowledge Center at  http://kc.forticare.com. Comments on Fortinet technical documentation  Please send information about any errors or omissions in this document, or any  Fortinet technical documentation, t
                    
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                        IPS overview and general configuration The FortiGate IPS IPS overview and general  configuration This section contains the following topics:  • The FortiGate IPS • Network performance • Monitoring the network and dealing with attacks • Using IPS sensors in a protection profile The FortiGate IPS An IPS is an Intrusion Prevention System for networks. While early systems  focused on intrusion detection, the continuing rapid growth of the Internet, and the  potential for the theft of sensitive data,
                    
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                        Network performance IPS overview and general configuration To create an IPS sensor, go to Intrusion Protection > IPS Sensor. See “IPS  sensors” on page 39 for details. To access the protection profile IPS sensor  selection, go to Firewall > Protection Profile, select Edit or Create New, and  select IPS.  To create a DoS Sensor, go to Intrusion Protection > DoS Sensor. See “DoS  sensors” on page 45 for details. When to use IPS IPS is best for large networks or for networks protecting highly sensi
                    
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                        IPS overview and general configuration Monitoring the network and dealing with attacks Controlling sessions Use this command to ignore sessions after a set amount of traffic has passed.  The default is 204800 bytes. config ips global set ignore-session-bytes  end Setting the buffer size Set the size of the IPS buffer. The size of the buffer is model-dependent. config ips global set socket-size  end Monitoring the network and dealing with attacks After configuring I
                    
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                        Monitoring the network and dealing with attacks IPS overview and general configuration 5 Select and configure authentication if required and enter the email addresses that  will receive the alert email. 6 Enter the time interval to wait before sending log messages for each logging  severity level. Note: If more than one log message is collected before an interval is reached, the messages  are combined and sent out as one alert email. 7 Select Apply. To access log messages from memory or on the l
                    
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                        IPS overview and general configuration Monitoring the network and dealing with attacks Anomaly The following log message is generated when an attack anomaly is detected: Message ID: 73001 Severity: Alert Message: attack_id= src= dst=  src_port= dst_port=  interface= src_int=  dst_int= status={clear_session | detected | dropped |  reset} proto= service=  msg=
                    
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                        Using IPS sensors in a protection profile IPS overview and general configuration Using IPS sensors in a protection profile IPS can be combined with other FortiGate features – antivirus, spam filtering, web  filtering, and web category filtering – to create protection profiles. Protection  profiles are then added to individual user groups and then to firewall policies, or  added directly to firewall policies. This section describes: • Creating a protection profile that uses IPS sensors • Adding p
                    
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                        IPS overview and general configuration Using IPS sensors in a protection profile Adding protection profiles to user groups  When creating a user group, select a protection profile that applies to that group.  Then, when configuring a firewall policy that includes user authentication, select  one or more user groups to authenticate. Each user group selected for  authentication in the firewall policy can have a different protection profile, and  therefore different IPS settings, applied to it. For
                    
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                        Using IPS sensors in a protection profile IPS overview and general configuration FortiGate IPS User Guide Version 3.0 MR7 16 01-30007-0080-20080916                                                                                                                                                                                                                                                                                                                                                                 
                    
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                        Predefined signatures IPS predefined signatures Predefined signatures This section describes: • IPS predefined signatures • Viewing the predefined signature list IPS predefined signatures Predefined signatures are arranged in alphabetical order. By default, some  signatures are disabled to prevent interference with common traffic, but logging is  enabled for all signatures.  Use the IPS sensor to customize the predefined signatures and apply appropriate  sensors to different protection profiles.
                    
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                        Viewing the predefined signature list Predefined signatures By default, the signatures are sorted by name. To sort the table by another  column, select the required column header name. Column Select to customize the signature information displayed in the table. You  can also readjust the column order. Settings Clear All Filters If you have applied filtering to the predefined signature list display, select  this option to clear all filters and display all the signatures.  Name The name of the sig
                    
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                        Predefined signatures Viewing the predefined signature list You should also review exactly how you use the information provided by the  logging feature. If you find that you do not review the information, it is best to turn  off IPS logging. Logging is best used to provide actionable intelligence. To create an IPS sensor 1 Go to Intrusion Protection > IPS Sensor.  2 Create a sensor and add IPS filters to it. FortiGate IPS User Guide Version 3.0 MR7 01-30007-0080-20080916 19                      
                    
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                        Viewing the predefined signature list Predefined signatures FortiGate IPS User Guide Version 3.0 MR7 20 01-30007-0080-20080916