IPアドレスのサブネット計算とかやる必要が時にはあります。
計算に慣れてしまえばいいんでしょうが、結構面倒な時もあります。
そんな時の「sipcalc」コマンドです。
「ipcalc」というコマンドもありますが、こっちのほうが良さげ。
使い方
# sipcalc -a -4 10.0.1.100/24 -[ipv4 : 10.0.1.100/24] - 0 [Classfull] Host address - 10.0.1.100 Host address (decimal) - 167772516 Host address (hex) - A000164 Network address - 10.0.0.0 Network class - A Network mask - 255.0.0.0 Network mask (hex) - FF000000 Broadcast address - 10.255.255.255 [CIDR] Host address - 10.0.1.100 Host address (decimal) - 167772516 Host address (hex) - A000164 Network address - 10.0.1.0 Network mask - 255.255.255.0 Network mask (bits) - 24 Network mask (hex) - FFFFFF00 Broadcast address - 10.0.1.255 Cisco wildcard - 0.0.0.255 Addresses in network - 256 Network range - 10.0.1.0 - 10.0.1.255 Usable range - 10.0.1.1 - 10.0.1.254 [Classfull bitmaps] Network address - 00001010.00000000.00000000.00000000 Network mask - 11111111.00000000.00000000.00000000 [CIDR bitmaps] Host address - 00001010.00000000.00000001.01100100 Network address - 00001010.00000000.00000001.00000000 Network mask - 11111111.11111111.11111111.00000000 Broadcast address - 00001010.00000000.00000001.11111111 Cisco wildcard - 00000000.00000000.00000000.11111111 Network range - 00001010.00000000.00000001.00000000 - 00001010.00000000.00000001.11111111 Usable range - 00001010.00000000.00000001.00000001 - 00001010.00000000.00000001.11111110 [Networks] Network - 10.0.1.0 - 10.0.1.255 (current)
CIDR表記変えれば計算も変わりますね。
# sipcalc -a -4 10.0.1.100/19 -[ipv4 : 10.0.1.100/19] - 0 [Classfull] Host address - 10.0.1.100 Host address (decimal) - 167772516 Host address (hex) - A000164 Network address - 10.0.0.0 Network class - A Network mask - 255.0.0.0 Network mask (hex) - FF000000 Broadcast address - 10.255.255.255 [CIDR] Host address - 10.0.1.100 Host address (decimal) - 167772516 Host address (hex) - A000164 Network address - 10.0.0.0 Network mask - 255.255.224.0 Network mask (bits) - 19 Network mask (hex) - FFFFE000 Broadcast address - 10.0.31.255 Cisco wildcard - 0.0.31.255 Addresses in network - 8192 Network range - 10.0.0.0 - 10.0.31.255 Usable range - 10.0.0.1 - 10.0.31.254 [Classfull bitmaps] Network address - 00001010.00000000.00000000.00000000 Network mask - 11111111.00000000.00000000.00000000 [CIDR bitmaps] Host address - 00001010.00000000.00000001.01100100 Network address - 00001010.00000000.00000000.00000000 Network mask - 11111111.11111111.11100000.00000000 Broadcast address - 00001010.00000000.00011111.11111111 Cisco wildcard - 00000000.00000000.00011111.11111111 Network range - 00001010.00000000.00000000.00000000 - 00001010.00000000.00011111.11111111 Usable range - 00001010.00000000.00000000.00000001 - 00001010.00000000.00011111.11111110 [Networks] Network - 10.0.0.0 - 10.0.31.255 (current)
NICを指定するとNICに割り当てられているIPアドレスに対して計算するようです。
# sipcalc eth0 -[int-ipv4 : eth0] - 0 [CIDR] Host address - 192.168.xxx.xxx Host address (decimal) - xxxxxxxxxx Host address (hex) - xxxxxxxx Network address - 192.168.xxx.xxx Network mask - 255.255.255.0 Network mask (bits) - 24 Network mask (hex) - xxxxxxxx Broadcast address - 192.168.xxx.xxx Cisco wildcard - 0.0.0.255 Addresses in network - 256 Network range - 192.168.xxx.xxx - 192.168.xxx.xxx Usable range - 192.168.xxx.xxx - 192.168.xxx.xxx -
同様にIPv6アドレスも計算できます。
手元のVMに割り当てられてたIP見たらこんな感じでした。
# sipcalc -6 fe80::a00:27ff:fe93:6526/64 -[ipv6 : fe80::a00:27ff:fe93:6526/64] - 0 [IPV6 INFO] Expanded Address - fe80:0000:0000:0000:0a00:27ff:fe93:6526 Compressed address - fe80::a00:27ff:fe93:6526 Subnet prefix (masked) - fe80:0:0:0:0:0:0:0/64 Address ID (masked) - 0:0:0:0:a00:27ff:fe93:6526/64 Prefix address - ffff:ffff:ffff:ffff:0:0:0:0 Prefix length - 64 Address type - Link-Local Unicast Addresses Network range - fe80:0000:0000:0000:0000:0000:0000:0000 - fe80:0000:0000:0000:ffff:ffff:ffff:ffff -
コマンドで計算できるのがすばらしいですね。
その他詳しい使い方は、「sipcalc --help」もしくはmanで。
今日はこんなところで。
