# IPv6 lifetime causes nm to disable connection [SOLVED]

## nagmat84

Hi,

in our dormitory we have 802.1X security with IPV4 and IPv6 both for wired and wireless network connection. IPv6 router advertisments are sent every 5 minutes with a route lifetime of 15 minutes and the O-Flag in the router advertisment is set to true. An DHCPv6 server hands out all additional information like DNS server.

I use

net-misc/networkmanager-0.8.4.0-r2:

kde-misc/networkmanagement-0.8_p20110714

net-misc/dhcp-4.2.3_p1

I use dhclient and not dhcpcd, because dhcpcd does not seem to support DHCPv6 at all. With dhclient everything essentially works, but every 15 minutes, i.e. if the IPv6 route lifetime is exceeded, I get the following message in my logs

<info> (eth0): DHCPv6 state changed nbi -> renew6

and this causes networkmanager to completely disable the network connection and restart an entire new connection. This is totally annoying, because this means my internet connection is lost for approximately 11 seconds every 15 minutes.

Why? If the DHCPv6 lease has to be renewed, actually not even the IPv6 addresses must be renewed, only the additional information like DNS server etc., it would be totally sufficient to start an DHCPv6 request and obtain the new DNS server. Actually the DNS server does not even change, but stays the same.

With IPv4 only everything works fine. The normal lease time of an IPv4 address is only 15 minutes, too, but if this one expires, the address is renewed just in time without a complete restart of the connection.

I would prefer to see the same behaviour with IPv6.Last edited by nagmat84 on Sat Jul 21, 2012 9:07 am; edited 1 time in total

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## gerard27

Have you followed the Gentoo guide?

http://www.gentoo.org/doc/en/ipv6.xml

I don't use networkmanager although I'm a KDE user.

And I use dhcpcd w/o problem.

My connection is wired only.

Gerard.

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## nagmat84

Hi,

the IPv6 guide you refer to is a guide how to build your own ipv6 router and how to create a tunnel on an ipv6 linux router if you have an ipv4 only isp. Nontheless I had a look at it and there is nothing special.

Moreover the guide only deals with pure IPv6 auto-configuration of the clients. This means the clients obtain an IPv6 address automatically based on the router advertisments. DNS and all other network base services are still handled by ipv4.

I have a setup that is sometimes called "stateless DHCPv6", because the address assignment is performed automatically and without an DHCPv6 server, but the address of the DNS server is obtained through DHCPv6.

You use dhcpcd? But for what? Stateful IPv6? Stateless IPv6? Or IPv4 only? What do you see in your /etc/resolv.conf?

EDIT: Corrected some typos.

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## mtfj

Possible to use dibbler-client instead?

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## nagmat84

No, because NetworkManager only supports dhcpcd and dhclient.

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## mtfj

I don't use Gentoo as client (server and router only) and don't use networkmanager. So I don't think I can help, but I found this

https://bugzilla.redhat.com/show_bug.cgi?id=753482

Can this be related to your problem?

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## nagmat84

Thank you,

the problem in the posting that you linked to is a little bit different, but essentially has the same cause.

The IPv6 router sends router advertisements with a lifetime of 300 seconds. The retransmit interval is between 100 and 200 seconds. Hence my laptop receives three fresh router advertisements before the initial one reaches its lifetime. A tcpdump reveals that the router advertisements are actually sent correctly.

But for some reason networkmanager makes the kernel to ignore all subsequent router advertisements, hence the router information is not updated and times out after 300 seconds. When this happens, the interface is disabled and networkmanager starts a complete new connection. Networkmanager waits for the first router advertisment, reconfigures the interface and ignores all subsequent updates again.

But if this is true, then this is a major bug in networkmanager and I wonder why nobody else seems the encounter this problem.

EDIT: Corrected some typosLast edited by nagmat84 on Fri Jul 20, 2012 12:52 pm; edited 1 time in total

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## loki_val

There was some bug in networkmanager and kernels >=3.3 that would have that effect that was just fixed in the latest ~arch version

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## nagmat84

OK, thank you for that information. Unfortunately I cannot try version >=0.9, because KDE 4 requires <net-misc/networkmanager-0.9. As soon as KDE 4 has support for newer versions of networkmanager, I will try them and give feedback if the issue is solved.

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## nagmat84

I upgraded to net-misc/networkmanager-0.9.4.0-r5 and kde-misc/networkmanagement-0.9.0.3 (both from ~amd64). The problem disappeared. So this was really a bug in networkmanager < 0.9 and kernels >=3.3.

Thank you.

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