OPNsense Forum

Archive => 18.7 Legacy Series => Topic started by: chris42 on September 17, 2018, 12:33:08 pm

Title: IPv6 router advertisements reset privacy extension lifetime
Post by: chris42 on September 17, 2018, 12:33:08 pm

Hi there,

I observed an odd behaviour on my laptop regarding the privacy extensions for IPv6. I correctly get a global dynamic IPv6 with lifetime 14400. However every few seconds the counter on the lifetime is reset to 14400, basically converting the temporary address into a fixed one.
I started a tcpdump and could observe, that the reset happens when a router advertisement for my prefix is received:

Code: [Select]

12:27:12.631357 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 120) fe80::1:1 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 120
hop limit 64, Flags [other stateful], pref medium, router lifetime 30s, reachable time 0s, retrans time 0s
  prefix info option (3), length 32 (4): a:b:c:d::/64, Flags [onlink, auto, router], valid time 86400s, pref. time 14400s
...
This has the 14400 seconds in there as well. Hence I assume that the router advertisement is resetting the ip configuration.

Question is now what to do, to have privacy extensions working again? Is it some configuration in opnsense or on the laptop?

Thanks
  Chris

Title: Re: IPv6 router advertisements reset privacy extension lifetime
Post by: marjohn56 on September 17, 2018, 12:54:16 pm

Privacy addresses are generated by the client itself, at least that is the case with Windows. If you do an ipconfig you will see several 2*** addresses, one is fixed and uses the prefix+mac ( mac bytes get moved around ). There is always a second and maybe a third, one of those will say Temporary Ipv6 address and it changes when you reboot.


Nice explanation here: [size=78%]http://computer-outlines.over-blog.com/article-windows-ipv6-privacy-addresses-118018020.html (http://computer-outlines.over-blog.com/article-windows-ipv6-privacy-addresses-118018020.html)[/size]

Title: Re: IPv6 router advertisements reset privacy extension lifetime
Post by: chris42 on September 17, 2018, 01:22:27 pm

Hi marjohn56,

Following the Ubuntu explanations (https://wiki.ubuntuusers.de/IPv6/Privacy_Extensions/), it should be different on Linux systems.
However that seems to be an issue on ubuntu systems then?!

Chris

Title: Re: IPv6 router advertisements reset privacy extension lifetime
Post by: marjohn56 on September 17, 2018, 08:18:45 pm

Don't know... only use Ubuntu if the need arises... not often. :)