Configure A Standard Ip Acl - Dell Force10 C150 Configuration Manual

In the following, TCP packets that are first fragments or non-fragmented from host 10.1.1.1 with TCP
destination port equal to 24 are permitted. Additionally, all TCP non-first fragments from host 10.1.1.1 are
permitted. All other IP packets that are non-first fragments are denied.
FTOS(conf)#ip access-list extended ABC
FTOS(conf-ext-nacl)#permit tcp host 10.1.1.1 any eq 24
FTOS(conf-ext-nacl)#permit tcp host 10.1.1.1 any fragment
FTOS(conf-ext-nacl)#deny ip any any fragment
FTOS(conf-ext-nacl)
To log all the packets denied and to override the implicit deny rule and the implicit permit rule for TCP/
UDP fragments, use a configuration similar to the following.
FTOS(conf)#ip access-list extended ABC
FTOS(conf-ext-nacl)#permit tcp any any fragment
FTOS(conf-ext-nacl)#permit udp any any fragment
FTOS(conf-ext-nacl)#deny ip any any log
FTOS(conf-ext-nacl)
Note the following when configuring ACLs with the
When an ACL filters packets it looks at the Fragment Offset (FO) to determine whether or not it is a fragment.
FO = 0 means it is either the first fragment or the packet is a non-fragment.
FO > 0 means it is dealing with the fragments of the original packet.
Permit ACL line with L3 information only, and the fragments keyword is present:
If a packet's L3 information matches the L3 information in the ACL line, the packet's fragment offset (FO) is
checked.
•If a packet's FO > 0, the packet is permitted.
•If a packet's FO = 0 , the next ACL entry is processed.
Deny ACL line with L3 information only, and the fragments keyword is present:
If a packet's L3 information does match the L3 information in the ACL line, the packet's fragment offset (FO) is
checked.
•If a packet's FO > 0, the packet is denied.
•If a packet's FO = 0, the next ACL line is processed.

Configure a standard IP ACL

To configure an ACL, use commands in the IP ACCESS LIST mode and the INTERFACE mode. The
following list includes the configuration tasks for IP ACLs:
For a complete listing of all commands related to IP ACLs, refer to the FTOS Command Line Interface
Reference document.
Refer to Configure an extended IP ACL on page 143
140 | IP Access Control Lists (ACL), Prefix Lists, and Route-maps
fragments
keyword.
to set up extended ACLs.