FreeBSD: IPv6 Configuration Set Prefixlen Value

Posted on in Categories last updated July 21, 2010

How do I set the prefixlen for an IPv6 address under FreeBSD operating systems?

You can set the prefixlen for an IPv6 address by editing /etc/rc.conf file, enter:
# vi /etc/rc.conf
Assuming that your IPv6 is address is 2001:48c8:7::2 for em0, enter:

ipv6_ifconfig_em0="2001:48c8:7::2 prefix 64"

Save and close the file. Restart networking. You can also set it at the shell prompt using the ifconfig command as follows:

ifconfig interFace inet6 ipv6IpAddress prefixlen Value
ifconfig fxp0 inet6 2001:48c8:7::2 prefixlen 64

Where,

  • fxp0 or em0 – FreeBSD NIC interface name
  • 2001:48c8:7::2 – IPv6 public IP address
  • 64 – IPv6 Prefixlen Value

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

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