3com 5500-ei pwr Guía De Referencia

 

1-22 

After completing the above configuration, you can use the display acl command to view the 

configuration information of the ACLs. 

rule [ rule-id ] { deny | permit } [ rule-string rule-mask offset ] &<1-8> [ time-range time-name ] 

undo rule rule-id  

User-defined ACL view 

rule-id: ID of an ACL rule, in the range of 0 to 65534. 

rule-string: User-defined ACL rule string. It must be an even hexadecimal number comprising 2 to 160 

hexadecimal numerals. 

rule-mask: User-defined mask of the ACL rule. It must be an even hexadecimal number containing 2 to 

160 hexadecimal numerals and be of the same length as that of the rule-string argument. This 

argument is used to perform the logical AND operations with packets. 

offset: Mask offset of the rule. It specifies a position in packets, from which the logical AND operation is 

to be performed. It ranges from 0 to 79 (in bytes).  

Note that:  

z 

The maximum value of the mask offset of the rule becomes one byte less when the rule-string 

argument has two more hexadecimal numerals. For example, when the rule-string contains two 

hexadecimal numerals, the maximum value of offset is 79 bytes; when the rule-string contains four 

hexadecimal numerals, the maximum value of offset is 78 bytes, and so on. 

z 

The valid length of the mask offset 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. However, the offset of 

the rule string bb cannot be greater than 79 bytes. 

z 

As shown in 

, the hardware rule of the Switch 5500-EI series 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. 

z 

With the Switch 5500-EI series, a user-defined rule string may or may not contain spaces and can 

be up to 32 bytes in length. It can occupy up to eight mask offset units and any two of the offset 

units cannot belong to the same offset group. Otherwise, the ACL cannot be applied successfully. 

Table 1-16 Offset units of a user-defined rule string 

0 to 3 

4 to 7 

8 to 11 

12 to 15 

16 to 19 

20 to 23 

24 to 27 

28 to 31