All fragmented packet is harmful?


Hello, all.


I read some documents that there are some cases that filter any fragmented packet at the border router using access-list like below.


http://www.cisconation.info/en/US/tech/tk648/tk361/technologies_tech_note09186a0080120f48.shtml


!
ip access-list extended ACL-INFRASTRUCTURE-IN
!
!--- Deny IP fragments using protocol-specific ACEs to aid in
!--- classification of attack traffic
!
deny tcp any any fragments
deny udp any any fragments
deny icmp any any fragments
deny ip any any fragments
!
!--- Deny all other IP traffic to any network device
!
deny ip any <infrastructure-address-space> <mask>
!
!--- Permit transit traffic
!
permit ip any any



So I'm not sure that it will be no problem to filter all fragmented packet or not
when my systems are web service.



Thanks in advance.

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