RA/Self assigned IPv6 instead of static

[dragon2611]

Proxmox 4.3-12/6894c9d9

Vmbr0 has been changed to an OVS bridge instead of a linux bridge

added 2001:1xxx:5XXX:XX::2 as an IPv6 with 2001:1xxx:5XXX:XX::2 rebooted and couldn't access the host over Ipv6

logged in on Ipv4 and found it had a completely different address in the 2001:1xxx:5:xxx:xx::/64 range (I presume the Providers router is sending out RA's then as the IP was based on the MAC)

I restarted networking and it then had the correct static IPv6, also rebooted the whole box again and this time it had the static Ipv6

I'm worried though that something is listening for RA's and may change the IP again.

This is a brand new proxmox install other than installing openvswitch and configuring networking I've not done anything with it yet.

Also as an aside will proxmox play nice without Ipv4?

Thinking of either removing the IPv4 from the management interface totally or just giving it an RFC1918 address on vmbr1 and passing it through a virtual router running NAT. (of course if that VM dies i'd only have access on IPv6)

 

[wbumiller]

Looks like autoconfiguration, see

# sysctl net.ipv6.conf |& grep autoconf

You can either use `/etc/sysctl.conf` or add `post-up` entries to `/etc/network/interfaces` to set autoconf to zero.
eg.

# /etc/sysctl.conf
net.ipv6.conf.all.autoconf=0
net.ipv6.conf.default.autoconf=0

 

[dragon2611]

Thanks,

Although perhaps it would be worth considering a feature enhancement to do that automatically if a static IPv6 is set using the web interface?
After all if one is configuring an IPv6 statically then usually it's a given that you don't want autoconfig to then go and assign something else.

 

[wbumiller]

Actually, there's a shorter way, there's an actual option which can be added to /etc/network/interfaces 'static' sections:

autoconf 0

But note that the interfaces(5) manpage claims that this actually defaults to 0 (off), when clearly the real default is to keep the sysctl-default (which does make sense...).

Adding this as a feature might be nice. We'd have to limit it to the `autoconf` entry and clearly distinguish all 3 cases (on/off/default) as parsing sysctl commands in `post/pre-up/down` lines would be too error prone. (eg. you can use the `sysctl` command or echo to /proc/sys/net/... manually, modify the default in pre-up or the actual value in post-up etc....)