OpenWrt/LEDE Project

  • Status Unconfirmed
  • Percent Complete
  • Task Type Bug Report
  • Category Base system
  • Assigned To No-one
  • Operating System All
  • Severity Low
  • Priority Very Low
  • Reported Version Trunk
  • Due in Version Undecided
  • Due Date Undecided
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Attached to Project: OpenWrt/LEDE Project
Opened by Mark Smith - 26.11.2018

FS#1971 - IPv6 ULA prefix announced with Infinite lifetimes, rather than RFC4861 defaults

Supply the following if possible:
- Device problem occurs on


- Software versions of OpenWrt/LEDE release, packages, etc.

* OpenWrt 18.06.1 r7258-5eb055306f / LuCI openwrt-18.06 branch (git-18.228.31946-f64b152)

- Steps to reproduce


1. IPv6 enabled by default, OpenWRT automatically generates a unique ULA prefix per RFC4193.

2. ULA prefix is announced with Infinite Preferred and Valid Lifetimes, rather than the RFC4861 defaults:

  1. AdvPreferredLifetime: Default: 604800 seconds (7 days)
  1. AdvValidLifetime: Default: 2592000 seconds (30 days)

e.g., using the ‘rdisc6’ utility to display RAs:

[root@opy mark]# rdisc6 wlp3s0
Soliciting ff02::2 (ff02::2) on wlp3s0...
Prefix : fdec:91f6:8c3a::/64

On-link                 :          Yes
Autonomous address conf.:          Yes
Valid time              :     infinite (0xffffffff)
Pref. time              :     infinite (0xffffffff)


Infinite lifetimes mean these ULA addresses never expire on a host and will always be considered valid source and destination addresses during RFC6724 source and destination address selection.

One consequence is that a mobile device that has a high uptime (e.g. a smartphone), moves between a number of IPv6 networks, and uses IPv6 privacy addresses, could end up with a lot of unusable ULA addresses on its network interface. They may accumulate continuously until the device is rebooted.


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