3com 4210 User Manual

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C
HAPTER
 22: ACL C
ONFIGURATION
 G
UIDE
# Define ACL 5000 to deny any ARP packet whose source IP address is 
192.168.0.1 from 8:00 to 18:00 everyday (provided that VLAN-VPN is not enabled 
on any port).In the ACL rule, 0806 is the ARP protocol number, 16 is the protocol 
type field offset of the internally processed Ethernet frame, c0a80001 is the 
hexadecimal form of 192.168.0.1, and 32 is the source IP address field offset of 
the internally processed ARP packet.
[3Com] acl number 5000
[3Com-acl-user-5000] rule 1 deny 0806 ffff 16 c0a80001 ffffffff 32 t
ime-range test 
# Apply ACL 5000 to Ethernet 1/0/1.
[3Com] interface Ethernet 1/0/1
[3Com-Ethernet1/0/1] packet-filter inbound user-group 5000 
Complete Configuration
#
acl number 5000
rule 1 deny 0806 ffff 16 c0a80001 ffffffff 32 time-range test
#
interface Ethernet1/0/1
packet-filter inbound user-group 5000 rule 1
#
time-range test 08:00 to 18:00 daily
Precautions
Some functions and protocols configured on the device may occupy ACL rule 
resources. The actual occupation varies with functions and protocols.
For a Switch 5500, if VLAN-VPN is not enabled, each packet in the switch 
carries one VLAN tag which is 4 bytes long; If VLAN-VPN is enabled on a port, 
each packet in the switch carries two VLAN tags, which are 8 bytes long. Pay 
attention to the above information when configuring a rule that matches 
specific fields of packets.
For an Switch 5500Gs Ethernet switch, each packet in the switch carries two 
VLAN tags, which are 8 bytes long. Pay attention to the above information 
when configuring a rule that matches specific fields of packets.
The command for defining a user-defined ACL rule is rule [ rule-id ] { deny | 
permit } [ rule-string rule-mask offset ] &<1-8> [ time-range time-name ], 
where, rule-id refers to the ACL number, rule-string the user-defined rule 
string, rule-mask the user-defined rule mask, and offset the rule mask offset.
If you specify multiple rule strings in an ACL rule, the valid length of the rule 
mask is 128 hexadecimal numerals (64 bytes).For example, assume that you 
specify a rule string of aa and set its offset to 2. If you continue to specify a rule 
string of bb, its offset must be in the range from 3 to 65 bytes. If you set the 
offset of the rule string aa to 3, the offset of the rule string bb must be in the 
range of 4 to 66 bytes, and so on. Note that the offset of the rule string bb 
cannot be greater than 79 bytes.
As shown in Table 2, the hardware rule of the Switch 5500/5500G logically 
divides the rule mask offset of a user-defined string into multiple offset units, 
each of which is 4-byte long. Available offset units fall into eight groups, which 
are numbered from Offset1 to Offset8