Opened 5 years ago

Closed 5 years ago

Last modified 5 years ago

#13547 closed defect (not_a_bug)

IPv6 old dynamic prefixes sticking

Reported by: anonymous Owned by: developers
Priority: normal Milestone: Chaos Calmer 15.05
Component: packages Version: Trunk
Keywords: Cc:


So I've got this problem that whenever wan reconnects, I get a new dynamic DHCPv6 prefix assigned to br-lan, and the old ones are not purged, leading to a bunch of IPv6 prefixes advertised by 6relayd, out of which only one (the most recent) is actually a working route.

Image example is forced reconnects to present the problem. But whenever WAN reconnects, another IPv6-prefix is added..without old one(s) being removed.

Many devices are getting confused by this since 6relayd keeps advertising them all. Eventually there'll be so many old prefixes that I think this is what makes the router stop responding all together, both on IPv4 and IPv6.

Pretty much stock configuration, currently on trunk r36663. Internet provider is OTE Greece, using PPPoE.

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Change History (5)

comment:1 Changed 5 years ago by anonymous

I forgot to mention I used to have a static prefix assigned to me via DHCPv6 during their beta test of IPv6, so a problem like this could never pop up.

Now that they've made IPv6 official the prefixes are all dynamic, so this problem showed up recently.

Somehow old prefixes must be removed I believe..

comment:2 Changed 5 years ago by anonymous

Further more if I press connect on br-lan to reset that interface when there are multiple old prefixes up, there seems to be a big chance of router locking up (no network access too it). Leds keeps on flashing though.

comment:3 Changed 5 years ago by cyrus

The ipv6 router requirements (rfc 6204)require sending out old prefixes for 2h with a preferred lifetime of 0 so that all clients know they are deprecated.

Unfortunately if you reconnect many times in these 2h they can pile up

Youcan check if the current behaviour is correct by installing "ip" and do a "ip address list". If all old prefixes have a preferred_lft of 0 / the deprecated flag set and a valid_lft < 7200s then we behave correctly.

If any old prefix stays for more than 2h then it would be a bug.

Last edited 5 years ago by cyrus (previous) (diff)

comment:4 Changed 5 years ago by cyrus

  • Resolution set to not_a_bug
  • Status changed from new to closed

comment:5 Changed 5 years ago by anonymous

So I guess it's the devices being problematic instead then. My printer stops working over ipv6 when above happens.

If only my dsl wouldnt loose sync every 30 minutes....

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