Understanding ipv6 lease time issue

Hi there,

I have a device with a static ipv4 and ipv6 lease in OpenWRT. The lease time is currently set to 'none' which appears to be the default .

While the device (running an RHEL 8 equivalent) seems to maintain the ipv4 address, sometimes the device seems to lose it's assigned ipv6 address and uses another, unassigned ipv6 address.

I don't have a clear idea how long it takes for this to happen, it's just something I've noticed occasionally, but it only ever happens with ipv6.

The only thing I have observed is that, when everything is working normally, the ip addr output on the machine shows a set of addresses (both ipv4 and ipv6) with lifetimes counting down from 12 hours.

When the device loses its address, all the ipv6 addresses are showing valid_lft as forever, while ipv4 still shows a countdown.

I confess I'm not well versed in how ipv6 works - ideas what could cause this?

Could be related to privacy extension (I assume you use NetworkManager? Check the connection setting details.)? What does ip -6 -d addr show reveal?

Could be related to privacy extension (I assume you use NetworkManager? Check the connection setting details.)? What does ip -6 -d addr show reveal?

Looking at the addresses now, after the 12 hours have expired, all of the addresses are now set to lifetime forever.

However, I found something interesting in the Network Manager log:
dhcp6 (enp1s0): unhandled event -42

I wonder if it would be easier to just tell network manager to have a fixed ipv6 address... Any suggestions?

@LilRedDog Do you think that would affect it?

The only thing I know about IPv6 is it ends with a 6.

Sorry.