ipv6 and failover

[Kristof Van Doorsselaere]

Dear dhcpd user mailing list,

Some time ago I posted a message about problems I encountered with dhcpd 4.3.2 and ldap support on centos 7.

Meanwhile to continue my work  i moved on to debian linux 8.1 and can confirm the issues I saw on centos 7 are not present on debian.

Now I was trying to figure out if and how I could configure failover for IPv6 dhcpd, but I’m a little confused about the current status, can someone tell me:

• what is the current status for ipv6 dhcpd failover
• Can we already implement this, or is this  feature not yet implemented

All I found so far is:

An RFC  which discusses a failover design

https://tools.ietf.org/html/draft-ietf-dhc-dhcpv6-failover-design-04

An RCF for DHCPv6 Failover Protocol

https://github.com/tomaszmrugalski/ietf-dhcpv6-fo/blob/master/draft-ietf-dhc-dhcpv6-failover-protocol-00.txt

Thanks in advance for you reply

Kristof Van Doorsselaere

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[sthaug]

> Now I was trying to figure out if and how I could configure failover for IPv6 dhcpd, but I�1rym a little confused about the current status, can someone tell me:
>
>
>   *   what is the current status for ipv6 dhcpd failover

It is not implemented in the ISC DHCP code. Furthermore, as far as I
know, the specifications for IPv6 DHCP failover are not ready yet.

Steinar Haug, Nethelp consulting, [hidden email]

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[Kristof Van Doorsselaere]

Is there any timing (roadmap) when it will be implemented?

Kristof Van Doorsselaere
hoofdmedewerker server- en netwerkbeheer
----------------------------------


Hogeschool Gent
Directie Financiën en ICT
Valentin Vaerwijckweg 1
BE-9000 Gent
T [phone]
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On 23/06/15 11:14, "[hidden email]" <[hidden email]> wrote:

>> Now I was trying to figure out if and how I could configure failover for IPv6 dhcpd, but I?$,1rym a little confused about the current status, can someone tell me:
>>
>>
>>   *   what is the current status for ipv6 dhcpd failover
>
>It is not implemented in the ISC DHCP code. Furthermore, as far as I
>know, the specifications for IPv6 DHCP failover are not ready yet.
>
>Steinar Haug, Nethelp consulting, [hidden email]
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[sthaug]

> Is there any timing (roadmap) when it will be implemented?

Consider the two documents you mentioned,

> RFC  which discusses a failover design
>
> https://tools.ietf.org/html/draft-ietf-dhc-dhcpv6-failover-design-04
>
> An RCF for DHCPv6 Failover Protocol
>
> https://github.com/tomaszmrugalski/ietf-dhcpv6-fo/blob/master/draft-ietf-dhc-dhcpv6-failover-protocol-00.txt

The first document is published as RFC 7031. The second document is from
March 2015, and is not yet an RFC.

I can't speak for ISC. However, I'm reasonably certain that they won't
be implementing DHCPv6 failover until the protocol design is "stable",
for some value of stable. I don't believe we're quite there yet...

Steinar Haug, Nethelp consulting, [hidden email]
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[Kristof Van Doorsselaere]

I was afraid for that answer :-(

Are there in the meantime any work-arounds to have some kind of a redundancy, how are Internet providers solving this problem, or aren’t they?

Kristof Van Doorsselaere
hoofdmedewerker server- en netwerkbeheer
----------------------------------


Hogeschool Gent
Directie Financiën en ICT
Valentin Vaerwijckweg 1
BE-9000 Gent
T [phone]
HoGent.be







On 23/06/15 12:15, "[hidden email]" <[hidden email]> wrote:

>> Is there any timing (roadmap) when it will be implemented?
>
>Consider the two documents you mentioned,
>
>> RFC  which discusses a failover design
>>
>> https://tools.ietf.org/html/draft-ietf-dhc-dhcpv6-failover-design-04
>>
>> An RCF for DHCPv6 Failover Protocol
>>
>> https://github.com/tomaszmrugalski/ietf-dhcpv6-fo/blob/master/draft-ietf-dhc-dhcpv6-failover-protocol-00.txt
>
>The first document is published as RFC 7031. The second document is from
>March 2015, and is not yet an RFC.
>
>I can't speak for ISC. However, I'm reasonably certain that they won't
>be implementing DHCPv6 failover until the protocol design is "stable",
>for some value of stable. I don't believe we're quite there yet...
>
>Steinar Haug, Nethelp consulting, [hidden email]

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[sthaug]

> I was afraid for that answer :-(
>
> Are there in the meantime any work-arounds to have some kind of a redundancy, how are Internet providers solving this problem, or aren�1ryt they?

There are no solutions today (that I know of) if you need customers to
*keep the same IPv6 addresses* in a failover scenario.

If you *don't* need the customers to keep the same addresses: Simply
configure two (or more) DHCPv6 servers with non-overlapping address
pools. IPv6 addresses are not a scarce resource...

Steinar Haug, Nethelp consulting, [hidden email]

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[Bjørn Mork]

[hidden email] writes:

>> I was afraid for that answer :-(
>>
>> Are there in the meantime any work-arounds to have some kind of a redundancy, how are Internet providers solving this problem, or aren$,1ryt they?
>
> There are no solutions today (that I know of) if you need customers to
> *keep the same IPv6 addresses* in a failover scenario.

If you are able to pre-allocate the addresses to each client (i.e. you
know the identity of all clients), then you can share/replicate the same
database to as many independent DHCPv6 servers as you like.

And if you don't know the identity of the clients, then then the next
paragraph will likely apply:

> If you *don't* need the customers to keep the same addresses: Simply
> configure two (or more) DHCPv6 servers with non-overlapping address
> pools. IPv6 addresses are not a scarce resource...

Exactly. You don't need failover unless you want to share a dynamically
managed address pool with fewer addresses than clients.  And why would
you want to do that with IPv6?

Take into account the necessary complexity of a failover solution, and I
think you have the explanation why this isn't implememted.  And IMHO
probably never will be.



Bjørn
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