Arch Linux

bch24

Member

Registered: 2011-11-20

Posts: 27

ip6v autoconfiguring?

Hello,

I just switched out my cable modem and now my box is acquiring a IPv6 address.

I use netctl for network setup and have it setup for a static IPv4:

    Interface=eno1
    IP=static
    Address=('192.168.1.50/24')
    Gateway='192.168.1.1'

I am clueless about IPv6 but how/why is it autoconfiguring IPv6 address?

So I did some googling and went to http://ipv6-test.com/

It show's my computers MAC address, the IP address assigned my computer.

Seems like a privacy issue to me.

Is my router/firewall is being bypassed?

mar04

Member

From: Poland

Registered: 2010-02-08

Posts: 117

Re: ip6v autoconfiguring?

It's called stateless address autoconfiguration. As for MAC address, read here: https://isc.sans.edu/diary/Enabling+Pri … IPv6/10966

rsmarples

Member

Registered: 2009-05-12

Posts: 287

Re: ip6v autoconfiguring?

The problem is that while private in the scheme linked above, they are also not stable. Which means they change frequently which could cause problems for some people, such as playing a long game and the address changes underneath you.
The correct solution is stable private addressing via SLAAC as specified in RFC7217 -  https://tools.ietf.org/html/rfc7217

dhcpcd supports this by default, but upgraders will need to add this to /etc/dhcpcd.conf

slaac private

Then dhcpcd will take over, but you may have to flush old addresses or reboot first and dhcpcd won't remove them.
Older kernels may also have duplicate link-local addresses, but this is fine and is fixed for newer kernels.