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Clever_Proxy
Premium
join:2004-05-14
Villa Park, IL

1 recommendation

[IPv6] Question regarding expiration of /64 leases

When we are leased a /64 prefix, how long does the lease last? Will there ever be a time where our prefix expires similar to an expiration of a leased IPv4 address?



tshirt
Premium,MVM
join:2004-07-11
Snohomish, WA
kudos:4

It is expected that IPv6 dynamics will be "sticky" similar to how current IPv4's are handled.
There is another thread here with posts on this in the last day or two, with a link to the offical CC statement on this.



whfsdude
Premium
join:2003-04-05
Washington, DC
Reviews:
·Comcast
reply to Clever_Proxy

said by Clever_Proxy:

When we are leased a /64 prefix, how long does the lease last? Will there ever be a time where our prefix expires similar to an expiration of a leased IPv4 address?

I haven't looked at the lease time but it should stay awhile as long as the DUID isn't changed.

Changing the DUID, triggers a new prefix.


whfsdude
Premium
join:2003-04-05
Washington, DC
reply to Clever_Proxy

I should also mention you can always announce a ULA for devices like printers. Most stacks should prefer the the global address but so announcing a second ULA prefix shouldn't be a problem.



Clever_Proxy
Premium
join:2004-05-14
Villa Park, IL

1 edit

Wouldn't that still cause problems for devices that require internet connectivity?

Example scenario:

For whatever reason, your leased prefix expires. Your router pulls a new prefix, but majority of your devices on your network are still addressed with the old prefix. So now you're in a situation where all of the devices on your network need to be told to pull new addresses from the router which will be publishing the new prefix if prefix delegation is set up correctly. Manual intervention would be required to get majority of devices to pull new addresses in the new prefix.

To me, it sounds like there would be pretty big problems if something like this were to happen on a large network.



tshirt
Premium,MVM
join:2004-07-11
Snohomish, WA
kudos:4

yes, that's why static addressing would be prefered in the long run.



dslcreature
Premium
join:2010-07-10
Seattle, WA
reply to Clever_Proxy

said by Clever_Proxy:

For whatever reason, your leased prefix expires. Your router pulls a new prefix, but majority of your devices on your network are still addressed with the old prefix.

It is possible to actively retract prefixes by announcing them with zero lifetimes. Whether your local advertisement daemon is smart enough to manage all of that when your assigned prefix changes would be an interesting test.

34764170

join:2007-09-06
Etobicoke, ON

said by dslcreature:

Whether your local advertisement daemon is smart enough to manage all of that when your assigned prefix changes would be an interesting test.

It would be to check to see if the RA implementation is buggy or not.


Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3
reply to Clever_Proxy

What about for routers that don't have an IPv6 DHCP server built in, or an option to turn Router Advertisements on or off?



whfsdude
Premium
join:2003-04-05
Washington, DC
Reviews:
·Comcast

said by Mike Wolf:

What about for routers that don't have an IPv6 DHCP server built in, or an option to turn Router Advertisements on or off?

Doesn't matter if you're using DHCPv6 or SLAAC, you still need router advertisements.


Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3

and how does one know if their equipment supports it?



whfsdude
Premium
join:2003-04-05
Washington, DC
Reviews:
·Comcast

said by Mike Wolf:

and how does one know if their equipment supports it?

If it doesn't you won't get an IPv6 address. RA's are pretty esential.


Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3

Good point. I just find it wierd that my one HP printer gets an IPv6 address and the DNSv6 section configures yet my other HP printer also gets an IPv6 address but its DNSv6 sectoins remains unconfigured lol.



whfsdude
Premium
join:2003-04-05
Washington, DC
Reviews:
·Comcast

said by Mike Wolf:

Good point. I just find it wierd that my one HP printer gets an IPv6 address and the DNSv6 section configures yet my other HP printer also gets an IPv6 address but its DNSv6 sectoins remains unconfigured lol.

The printer likely doesn't support DHCPv6 and is using SLAAC. You'd have to push a DNS server with RDNSS. I doubt any consumer routers are pushing DNS via RDNSS.


Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3

Dunno, the printer that is getting the DNSv6 info is a small business model, while the printer that isn't is an enterprise business model.