HP 2520-8 Configuration Manual page 75

IPv6 Mask
IPv6 Address Entered with the "ipv6
authorized-managers" Command
Other Authorized IPv6 Addresses
Figure 3-5. Example: How Hexadecimal C in a Mask Authorizes Four IPv6 Manager Addresses
to 0 ("off") and allow the corresponding bits in an authorized IPv6 address to
be either "on" or "off". As a result, only the four IPv6 addresses shown in Figure
3-5 are allowed access.
1st 2nd
Block Block
FFFF FFFF
2001 DB8
2001 DB8
2001 DB8
2001 DB8
Example. Figure 3-6 shows an example in which a mask is applied to the
IPv6 address: 2001:DB8:0000:0000:244:17FF:FEB6:D37D/64. The specified mask
FFFF:FFFF:FFFF:FFF8:FFFF:FFFF:FFFF:FFFF configures eight management stations as
authorized IP manager stations.
Note that, in this example, the IPv6 mask is applied as follows:
■ Eight management stations in different subnets are authorized by the
value of the fourth block (FFF8) in the 64-bit prefix ID (FFFF:FFFF:FFFF:FFF8)
of the mask. (The fourth block of the prefix ID is often used to define
subnets in an IPv6 network.)
The binary equivalent of FFF8 that is used to specify valid subnet IDs in the
IPv6 addresses of authorized stations is: 1111 1111 1111 1000.
The three "off" bits (1000) in the last part of the this block (FFF8) of the
mask allow for eight possible authorized IPv6 stations:
2001:DB8:0000:0000:244:17FF:FEB6:D37D
2001:DB8:0000:0001:244:17FF:FEB6:D37D
2001:DB8:0000:0002:244:17FF:FEB6:D37D
2001:DB8:0000:0003:244:17FF:FEB6:D37D
2001:DB8:0000:0004:244:17FF:FEB6:D37D
2001:DB8:0000:0005:244:17FF:FEB6:D37D
2001:DB8:0000:0006:244:17FF:FEB6:D37D
2001:DB8:0000:0007:244:17FF:FEB6:D37D
■ Each authorized station has the same 64-bit device ID (244:17FF:FEB6:D37D)
because the value of the last four blocks in the mask is FFFF (binary value
1111 1111).
IPv6 Management Security Features
3rd 4th 5th
Block Block Block
FFFF FFFF FFFF
0000 0000 244
0000 0000 244
0000 0000 244
0000 0000 244
Authorized IP Managers for IPv6
6th 7th 8th
Block Block Block
FFFF FFFF FFFC
17FF FEB6 D37D
17FF FEB6 D37C
17FF FEB6 D37E
17FF FEB6 D37F
3-7