Fortinet FortiGate FortiGate-50 - Page 9

Contents
FortiGate-50 Installation and Configuration Guide 9
Network Intrusion Detection System (NIDS) ................................................... 193
Detecting attacks ............................................................................................................ 193
Selecting the interfaces to monitor.............................................................................. 194
Disabling the NIDS...................................................................................................... 194
Configuring checksum verification .............................................................................. 194
Viewing the signature list ............................................................................................ 195
Viewing attack descriptions......................................................................................... 195
Enabling and disabling NIDS attack signatures .......................................................... 196
Adding user-defined signatures .................................................................................. 196
Preventing attacks .......................................................................................................... 197
Enabling NIDS attack prevention ................................................................................ 197
Enabling NIDS attack prevention signatures .............................................................. 198
Setting signature threshold values.............................................................................. 198
Configuring synflood signature values ........................................................................ 200
Logging attacks............................................................................................................... 200
Logging attack messages to the attack log................................................................. 200
Reducing the number of NIDS attack log and email messages.................................. 201
Antivirus protection........................................................................................... 203
General configuration steps............................................................................................ 203
Antivirus scanning........................................................................................................... 204
File blocking.................................................................................................................... 205
Blocking files in firewall traffic ..................................................................................... 205
Adding file patterns to block........................................................................................ 205
Blocking oversized files and emails ................................................................................ 206
Configuring limits for oversized files and email........................................................... 206
Exempting fragmented email from blocking.................................................................... 206
Viewing the virus list ....................................................................................................... 206
Web filtering ....................................................................................................... 207
General configuration steps............................................................................................ 207
Content blocking ............................................................................................................. 208
Adding words and phrases to the banned word list .................................................... 208
URL blocking................................................................................................................... 209
Using the FortiGate web filter ..................................................................................... 209
Using the Cerberian web filter..................................................................................... 212
Script filtering .................................................................................................................. 214
Enabling the script filter............................................................................................... 214
Selecting script filter options ....................................................................................... 214
Exempt URL list .............................................................................................................. 215
Adding URLs to the exempt URL list .......................................................................... 215
Email filter........................................................................................................... 217
General configuration steps............................................................................................ 217