1
Download User Manual - Neteon Technologies
Transcript
6.11 CIDR (Classless InterDomain Routing) IP netmasks and CIDR are notations, which define an address space containing multiple IP addresses. In this case, an address space in which the addresses follow one another sequentially is treated as a network. To define a range of IP addresses for the mGuard e.g. when configuring the firewall, it may be necessary to use the CIDR notation to specify the address space. The following table presents the IP netmask on the left and the corresponding CIDR notation on the right. IP-Netmask 255.255.255.255 255.255.255.254 255.255.255.252 255.255.255.248 255.255.255.240 255.255.255.224 255.255.255.192 255.255.255.128 binary 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111110 11111100 11111000 11110000 11100000 11000000 10000000 CIDR 32 31 30 29 28 27 26 25 255.255.255.0 255.255.254.0 255.255.252.0 255.255.248.0 255.255.240.0 255.255.224.0 255.255.192.0 255.255.128.0 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111110 11111100 11111000 11110000 11100000 11000000 10000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 24 23 22 21 20 19 18 17 255.255.0.0 255.254.0.0 255.252.0.0 255.248.0.0 255.240.0.0 255.224.0.0 255.192.0.0 255.128.0.0 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111110 11111100 11111000 11110000 11100000 11000000 10000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 16 15 14 13 12 11 10 9 255.0.0.0 254.0.0.0 252.0.0.0 248.0.0.0 240.0.0.0 224.0.0.0 192.0.0.0 128.0.0.0 11111111 11111110 11111100 11111000 11110000 11100000 11000000 10000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 8 7 6 5 4 3 2 1 0.0.0.0 00000000 00000000 00000000 00000000 0 Example: 192.168.1.0 / 255.255.255.0 corresponds to 192.168.1.0/24 in CIDR notation 141 of 157
