
Contents
FortiGate-400 Installation and Configuration Guide 11
Network Intrusion Detection System (NIDS) ................................................... 249
Detecting attacks ............................................................................................................ 249
Selecting the interfaces to monitor.............................................................................. 250
Disabling the NIDS...................................................................................................... 250
Configuring checksum verification .............................................................................. 250
Viewing the signature list ............................................................................................ 251
Viewing attack descriptions......................................................................................... 251
Enabling and disabling NIDS attack signatures .......................................................... 252
Adding user-defined signatures .................................................................................. 252
Preventing attacks .......................................................................................................... 253
Enabling NIDS attack prevention ................................................................................ 253
Enabling NIDS attack prevention signatures .............................................................. 254
Setting signature threshold values.............................................................................. 254
Configuring synflood signature values ........................................................................ 256
Logging attacks............................................................................................................... 256
Logging attack messages to the attack log................................................................. 256
Reducing the number of NIDS attack log and email messages.................................. 257
Antivirus protection........................................................................................... 259
General configuration steps............................................................................................ 259
Antivirus scanning........................................................................................................... 260
File blocking.................................................................................................................... 261
Blocking files in firewall traffic ..................................................................................... 262
Adding file patterns to block........................................................................................ 262
Quarantine ...................................................................................................................... 263
Quarantining infected files .......................................................................................... 263
Quarantining blocked files........................................................................................... 263
Viewing the quarantine list .......................................................................................... 264
Sorting the quarantine list ........................................................................................... 264
Filtering the quarantine list.......................................................................................... 265
Deleting files from quarantine ..................................................................................... 265
Downloading quarantined files.................................................................................... 265
Configuring quarantine options ................................................................................... 265
Blocking oversized files and emails ................................................................................ 266
Configuring limits for oversized files and email........................................................... 266
Exempting fragmented email from blocking.................................................................... 266
Viewing the virus list ....................................................................................................... 266
Web filtering ....................................................................................................... 267
General configuration steps............................................................................................ 267
Content blocking ............................................................................................................. 268
Adding words and phrases to the banned word list .................................................... 268