IPv6 dynamically allocated pool's valid-lifetime

RouterOS General
1

Hi,

Forking this thread:
http://forum.mikrotik.com/t/what-is-the-lifetime-of-prefixes-delegated-by-the-dhcpv6-server/167744/1

TLDR: the

valid-lifetime

and

preferred-lifetime

of IPv6 dynamically allocated pool is mismatched of what the ISP actually sends.
My current version is MikroTik RouterOS 7.18.2.

Here is what

/ipv6/pool/print detail

says:

Flags: D - dynamic 
 0 D name="isp-v6" prefix=2a01:XXXX:XXXX:XXXX::/64 prefix-length=64 
     expires-after=3h57m55s

Here is what the ND value is:

/ipv6/nd/prefix/print detail 
Flags: X - disabled, I - invalid; D - dynamic 
 0  D prefix=2a01:xxxx:xxxx:xxxx::/64 6to4-interface=none interface=bridge 
      on-link=yes autonomous=yes valid-lifetime=4w2d preferred-lifetime=1w

The effect of this is having depricated on my hosts configured via SLAAC, which may lead to all kind of issues.

Is this considered a bug in RouterOS ?

2

For this reason (and others, like when you make modification to a vlan or bridge interface, the interface immediately gets new prefix from the pool) I’ve been setting valid lifetime and preferred lifetime on all of my routers to only 10 minutes. Then I would have to deal with wrong prefixes for at most 10 minutes (including for situations where the router reboots and forgets to make to old prefix deprecated).

Of course, this increases multicast traffic if you have a lot of devices in your network, but I think it’s still negligible.
ipv6-nd-lifetime.png

3

Ahhh! I didn’t know this option is available.

Thank you so much pointing it out for me, cheers!
This should put my concerns regarding having deprecated for weeks on my devices.