Arch Linux

kbar

Member

Registered: 2012-04-25

Posts: 7

[SOLVED-ISH] ipv6 dropping intermittently, fixed with netcfg -r

So ipv6 connectivity drops randomly, without any interruption to ipv4.

I'm not really sure what logs to look into to check what the real error is.

However, a netcfg -r eth0 immediately after it drops out reconnects me to ipv6, and nobody else on the same network+host machine has the same issue. Therefore I'm assuming that this has something to do with my system. I'm running arch in a KVM.

Any ideas? Right now I just have a script running on cron that checks if ipv6 connectivity is broken and does netcfg -r, but obviously this isn't a valid solution.

This is what my profile looks like:

CONNECTION='ethernet'
DESCRIPTION='ipv6+ipv4 eth0'
INTERFACE='eth0'

IP=static
ADDR=69.85.88.224
NETMASK=24
ROUTES=
GATEWAY=69.85.88.1

IP6=static
ADDR6=(2606:df00:2::290c:6232/64 2606:df00:2::52c9:3080/64 2606:df00:2::a81:cb82/64 2606:df00:2::a1ac:9470/64 2606:df00:2::3ef6:a7e3/64)

(the gateway specified in ipv4 is the same router for ipv6)

Thanks.

[EDIT] I just checked my irc logs and it looks like it drops every 30 minutes on the hour and half hour, but there's nothing in crontab.

Last edited by kbar (2012-04-30 03:39:03)

Gcool

Member

Registered: 2011-08-16

Posts: 1,456

Re: [SOLVED-ISH] ipv6 dropping intermittently, fixed with netcfg -r

Are you using ip6tables to filter/restrict traffic on the Arch install (or the host)?

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Burninate!

kbar

Member

Registered: 2012-04-25

Posts: 7

Re: [SOLVED-ISH] ipv6 dropping intermittently, fixed with netcfg -r

no I am not.

ghen

Member

From: Belgium

Registered: 2010-08-31

Posts: 124

Re: [SOLVED-ISH] ipv6 dropping intermittently, fixed with netcfg -r

What do you mean exactly with "IPv6 connectivity drops" ?  Do you lose the IP address on the interface, or is it still there?  Do you lose your default route?  netcfg -r reinitializes all of that, you should try to find out what exactly gets lost.

Look at differences between "ip -6 addr list" and "ip -6 route show" when you have connectivity vs. when you don't.

kbar

Member

Registered: 2012-04-25

Posts: 7

Re: [SOLVED-ISH] ipv6 dropping intermittently, fixed with netcfg -r

when it's up, I see this in ip -6 route show:

default via fe80::20a:b8ff:fe6c:31b9 dev eth0  proto kernel  metric 1024  expires 1760sec

I'm assuming that the expires part is what makes my ipv6 drop. how would I disable it?

ghen

Member

From: Belgium

Registered: 2010-08-31

Posts: 124

Re: [SOLVED-ISH] ipv6 dropping intermittently, fixed with netcfg -r

Your router announces that lifetime in IPv6 "router advertisements".  But it should (re-)announce that frequently.  Either check/fix its settings, or just configure the default gateway statically on the host?

kbar

Member

Registered: 2012-04-25

Posts: 7

Re: [SOLVED-ISH] ipv6 dropping intermittently, fixed with netcfg -r

How would I set the default gateway for ipv6? It's the same router as the ipv4 gateway. So if I add GATEWAY6, it'll give me an error.

kbar

Member

Registered: 2012-04-25

Posts: 7

Re: [SOLVED-ISH] ipv6 dropping intermittently, fixed with netcfg -r

found the issue.

https://bugs.archlinux.org/task/28887?s … &closedto=

should fix it. meanwhile i manually changed the default route to add the ipv6 gateway.