linux下面禁止ipv6

Here's the summary of what I can think of, with alternate methods in case the first one doesn't work with you:

• Debian kernel 2.4:

• In /etc/modutils, change the line
  alias net-pf-10 ipv6
  to
  alias net-pf-10 off
  alias ipv6 off
• Reboot.

• Debian kernel 2.6/Ubuntu ("official" method)/Fedora Core (method 1):

• In /etc/modprobe.d/aliases, change the line
  alias net-pf-10 ipv6
  to
  
  alias net-pf-10 off
  alias ipv6 off
• Reboot.

• Debian kernel 2.6/Ubuntu (alternate method):

• In /etc/modprobe.d/blacklist, add a line
  blacklist ipv6
• Reboot.

• RHEL/CentOS:

• In /etc/modprobe.conf, make sure you have
  alias net-pf-10 off
  alias ipv6 off
• Reboot.

• RHEL/CentOS/Fedora Core (method 2)/Mandriva (method 1):

• In /etc/sysconfig/network, add a line
  NETWORKING_IPV6="no"
• Reboot.

• SuSE 9.0:

• In /etc/modules.conf, change the line
  alias net-pf-10 ipv6
  to
  alias net-pf-10 off
  alias ipv6 off
• Reboot.

• SuSE 9.1/9.2/9.3/10.0 ("official" method):

• In /etc/modprobe.conf, change the line
  alias net-pf-10 ipv6
  to
  alias net-pf-10 ipv6
  install ipv6 /bin/true
• Reboot.

• SuSE 9.1/9.2/9.3/10.0 (alternate method)/Mandriva (method 2)/Slackware:

• In /etc/modprobe.conf, make sure you change
  alias net-pf-10 ipv6
  to
  alias net-pf-10 off
  alias ipv6 off
• Reboot.

• Gentoo:

• In /etc/modules.d/aliases, make sure you change
  alias net-pf-10 ipv6
  to
  alias net-pf-10 off
  alias ipv6 off
• Reboot.

NOTES:

• In distros using /etc/modprobe.conf, beware that you might get overriden by /etc/modprobe.conf.local or by /etc/modprobe.d/*.
• If you disable IPv6, I suppose you don't need tunnels either. You could also add there:
  install sit0 /bin/true
• A last "anti-IPv6" issue: don't forget the old trick of checking if your Firefox has IPv6 disabled:
  • CTRL+L, about:config (Enter)
  • Filter by ipv6.
  • Set network.dns.disableIPv6 to true.