Fortinet FortiGate 4000 - Manual (Page 12)

Contents
12
Fortinet Inc.
Network Intrusion Detection System (NIDS) ................................................... 271
Detecting attacks ............................................................................................................ 271
Selecting the interfaces to monitor.............................................................................. 272
Disabling monitoring interfaces................................................................................... 272
Configuring checksum verification .............................................................................. 272
Viewing the signature list ............................................................................................ 273
Viewing attack descriptions......................................................................................... 273
Disabling NIDS attack signatures ............................................................................... 274
Adding user-defined signatures .................................................................................. 274
Preventing attacks .......................................................................................................... 276
Enabling NIDS attack prevention ................................................................................ 276
Enabling NIDS attack prevention signatures .............................................................. 276
Setting signature threshold values.............................................................................. 277
Logging attacks............................................................................................................... 278
Logging attack messages to the attack log................................................................. 278
Reducing the number of NIDS attack log and email messages.................................. 278
Antivirus protection........................................................................................... 281
General configuration steps ............................................................................................ 281
Antivirus scanning........................................................................................................... 282
File blocking .................................................................................................................... 283
Blocking files in firewall traffic ..................................................................................... 284
Adding file patterns to block........................................................................................ 284
Blocking oversized files and emails ................................................................................ 285
Configuring limits for oversized files and email........................................................... 285
Exempting fragmented email from blocking.................................................................... 285
Viewing the virus list ....................................................................................................... 286
Web filtering ....................................................................................................... 287
General configuration steps ............................................................................................ 287
Content blocking ............................................................................................................. 288
Adding words and phrases to the Banned Word list ................................................... 288
Clearing the Banned Word list .................................................................................... 289
Backing up the Banned Word list................................................................................ 290
Restoring the Banned Word list .................................................................................. 290
URL blocking................................................................................................................... 291
Configuring FortiGate Web URL blocking................................................................... 291
Configuring FortiGate Web pattern blocking............................................................... 294
Configuring Cerberian URL filtering ................................................................................ 294
Installing a Cerberian license key ............................................................................... 295
Adding a Cerberian user ............................................................................................. 295
Configuring Cerberian web filter ................................................................................. 295
Enabling Cerberian URL filtering ................................................................................ 296