CentOS

2006/7/31 04:31 PM 更新

IPv6の無効化

CentOS 4.3はデフォルトでIPv6が有効になっており自動的にIPアドレスが割り当てられる。
管理外のネットワークの存在はセキュリティホールになりかねないのでIPv6を無効化する。
（通信の遅延対策という意味合いもある）

　　/etc/modprobe.conf 
alias eth0 e100
alias usb-controller uhci-hcd

# Turn off IPv6
alias net-pf-10 off
alias ipv6 off
OSを再起動して設定変更を有効にする。
　　●設定変更前 
# /sbin/ifconfig -a
eth0      Link encap:Ethernet  HWaddr 00:AA:11:BB:22:CC
          inet addr:192.168.1.xx  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::2aa:11ff:febb:22cc/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:90275 errors:0 dropped:0 overruns:0 frame:0
          TX packets:76913 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:55465742 (52.8 MiB)  TX bytes:10428399 (9.9 MiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:2262 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2262 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:298777 (291.7 KiB)  TX bytes:298777 (291.7 KiB)

sit0      Link encap:IPv6-in-IPv4
          NOARP  MTU:1480  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
　　●設定変更後 
# /sbin/ifconfig -a
eth0      Link encap:Ethernet  HWaddr 00:AA:11:BB:22:CC
          inet addr:192.168.1.xx  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:130 errors:0 dropped:0 overruns:0 frame:0
          TX packets:88 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:12584 (12.2 KiB)  TX bytes:9522 (9.2 KiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:6 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:767 (767.0 b)  TX bytes:767 (767.0 b)