Debian下IPv6設定主地址 Set primary IPv6 address under Debian Linux

Linux下選擇IPv6主地址是按照一定規則來的 #RFC3484 (davidc)

1. Prefer same address. (i.e. destination is local machine)
2. Prefer appropriate scope. (i.e. smallest scope shared with the destination)
3. Avoid deprecated addresses.
4. Prefer home addresses.
5. Prefer outgoing interface. (i.e. prefer an address on the interface we're sending out of)
6. Prefer matching label.
7. Prefer public addresses.
8. Use longest matching prefix.

如果你有一個/64的段，并且為網卡分配了多個同段地址的時候，Linux會自動選擇最后添加的地址作為主地址。

要設定個性化主地址，可以在添加非主地址的時候加上[lifetime]屬性，將preferred_lft設為0。Linux將自動地把這些地址排除在主地址選擇范圍之外。

例：

ip addr -6 add xx:xx:xx:xx::8888/xx dev eth0 #?這個地址將包括在主地址選擇中

ip addr -6 add xx:xx:xx:xx::A/xx dev eth0 preferred_lft 0 #?這個地址不會當做主地址

Works Cited:

1. ?davidc, "IPv6 Source Address Selection on Linux" May 11, 2009, Retrieved from http://www.davidc.net/networking/ipv6-source-address-selection-linux