Using Authorized IP Managers

Building IP Masks

Table 10-1. Analysis of IP Mask for Single-Station Entries

 

1st

2nd

3rd

4th

Manager-Level or Operator-Level Device Access

 

Octet

Octet

Octet

Octet

 

 

 

 

 

 

 

IP Mask

255

255

255

255

The “255” in each octet of the mask specifies that only the exact value in

Authorized

10

28

227

125

that octet of the corresponding IP address is allowed. This mask allows

management access only to a station having an IP address of 10.33.248.5.

Manager IP

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Configuring Multiple Stations Per Authorized Manager IP Entry

The mask determines whether the IP address of a station on the network meets the criteria you specify. That is, for a given Authorized Manager entry, the switch applies the IP mask to the IP address you specify to determine a range of authorized IP addresses for management access. As described above, that range can be as small as one IP address (if 255 is set for all octets in the mask), or can include multiple IP addresses (if one or more octets in the mask are set to less than 255).

If a bit in an octet of the mask is “on” (set to 1), then the corresponding bit in the IP address of a potentially authorized station must match the same bit in the IP address you entered in the Authorized Manager IP list. Conversely, if a bit in an octet of the mask is “off” (set to 0), then the corresponding bit in the IP address of a potentially authorized station on the network does not have to match its counterpart in the IP address you entered in the Authorized Manager IP list. Thus, in the example shown above, a “255” in an IP Mask octet (all bits in the octet are “on”) means only one value is allowed for that octet—the value you specify in the corresponding octet of the Authorized Manager IP list. A “0” (all bits in the octet are “off”) means that any value from 0 to 255 is allowed in the corresponding octet in the IP address of an authorized station. You can also specify a series of values that are a subset of the 0-255 range by using a value that is greater than 0, but less than 255.

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