HP 6120XG HP ProCurve Series 6120 Blade Switches IPv6 Configuration Guide - Page 140

Example., The mask is

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IPv6 Management Security Features Authorized IP Managers for IPv6 Example. Figure 6-3 shows an example in which a mask that authorizes switch access to four management stations is applied to the IPv6 address: 2001:DB8:0000:0000:244:17FF:FEB6:D37D. The mask is: FFFF:FFFF:FFFF:FFF8:FFFF:FFFF:FFFF:FFFC. 1st 2nd 3rd 4th 5th 6th 7th 8th Manager- or Operator-Level Access Block Block Block Block Block Block Block Block IPv6 Mask FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFC The "F" value in the first 124 bits of the IPv6 Address 2001 DB8 0000 0000 244 17FF FEB6 D37D mask specifies that only the exact value of each corresponding bit in an authorized IPv6 address is allowed. However, the "C" value in the last four bits of the mask allows four possible combinations (D37C, D37D, D37E, and D37F) in the last block of an authorized IPv6 address. Figure 6-3. Example: Mask for Configuring Four Authorized IPv6 Manager Stations Last block in Mask: FFFC Last block in IPv6 Address: D37D Bit Numbers Bit Bit Bit 15 14 13 Bit Value F FFFC: Last Block in Mask Bit Bit Bit Bit Bit 12 11 10 9 8 F Bit Bit Bit Bit Bit Bit Bit Bit 7 65 4 3 2 1 0 F C D37D: Last Block in IPv6 Address Bit Setting: = 1 (On) = 0 (Off) Figure 6-4. Example: How a Mask Determines Four Authorized IPv6 Manager Addresses As shown in Figure 6-4, if you use a mask of FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFC with an IPv6 address, you can authorize four IPv6-based stations to access the switch. In this mask, all bits except the last two are set to 1 ("on"); the binary equivalent of hexadecimal C is 1100. Therefore, this mask requires the first corresponding 126 bits in an authorized IPv6 address to be the same as in the specified IPv6 address: 2001:DB8:0000:0000:244:17FF:FEB6:D37C. However, the last two bits are set 6-8

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IPv6 Management Security Features
Authorized IP Managers for IPv6
Example.
Figure 6-3 shows an example in which a mask that authorizes
switch access to four management stations is applied to the IPv6 address:
2001:DB8:0000:0000:244:17FF:FEB6:D37D
. The mask is:
FFFF:FFFF:FFFF:FFF8:FFFF:FFFF:FFFF:FFFC
.
1st
Block
2nd
Block
3rd
Block
4th
Block
5th
Block
6th
Block
7th
Block
8th
Block
Manager- or Operator-Level Access
IPv6 Mask
FFFF
FFFF
FFFF
FFFF
FFFF
FFFF
FFFF
FFFC±
IPv6 Address
2001
DB8
0000
0000
244
17FF
FEB6
D37D±
The “F” value in the first 124 bits of the
mask specifies that only the exact value
of each corresponding bit in an
authorized IPv6 address is allowed.
However, the “C” value in the last four
bits of the mask allows four possible
combinations (D37C, D37D, D37E, and
D37F) in the last block of an authorized
IPv6 address.
Figure 6-3.
Example: Mask for Configuring Four Authorized IPv6 Manager Stations
Last block in Mask: FFFC
Last block in IPv6 Address: D37D
Bit Numbers
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Bit Value
F
F
F
C
FFFC: Last Block
in Mask
D37D: Last Block
in IPv6 Address
Bit Setting:
= 1 (On)
= 0 (Off)
Figure 6-4.
Example: How a Mask Determines Four Authorized IPv6 Manager Addresses
As shown in Figure 6-4, if you use a mask of
FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFC
with an IPv6 address, you can authorize
four IPv6-based stations to access the switch. In this mask, all bits except the
last two are set to 1 (“on”); the binary equivalent of hexadecimal
C
is 1100.
Therefore, this mask requires the first corresponding 126 bits in an authorized
IPv6 address to be the same as in the specified IPv6 address:
2001:DB8:0000:0000:244:17FF:FEB6:D37C. However, the last two bits are set
6-8