MAAS

NTP servers must be IPv4 for use with ISC dhcpd

Bug #1606499 reported by Gavin Panella
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
MAAS
Fix Released
High
Gavin Panella

Bug Description

ISC dhcpd (4.3.3-5ubuntu12.1 in Xenial) rejects configuration containing
NTP servers with IPv6 addresses:

  /path/to/dhcpd.conf line 81: semicolon expected.
    option ntp-servers 12.178.81.19, ntp.example.G99qnq, fd2a:
                                                              ^

In MAAS do we:

- Prevent users from configuring NTP servers with IPv6 addresses,

- Eliminate IPv6 only NTP servers from the DHCP configuration,

- Stop publishing the ntp-servers option,

- Or something else?

Tags: ntp

Related branches

lp:~allenap/maas/ntp-ipv4-ipv6-dhcp-options
Mike Pontillo (community): Approve
Diff: 623 lines (+271/-40)
10 files modified
src/provisioningserver/dhcp/config.py (+49/-0)
src/provisioningserver/dhcp/testing/config.py (+21/-3)
src/provisioningserver/dhcp/tests/test_config.py (+92/-22)
src/provisioningserver/rpc/tests/test_clusterservice.py (+7/-0)
src/provisioningserver/rpc/tests/test_dhcp.py (+12/-6)
src/provisioningserver/templates/dhcp/dhcpd.conf.template (+8/-3)
src/provisioningserver/templates/dhcp/dhcpd6.conf.template (+8/-3)
src/provisioningserver/testing/network.py (+38/-0)
src/provisioningserver/utils/tests/test_text.py (+29/-0)
src/provisioningserver/utils/text.py (+7/-3)
Revision history for this message
Blake Rouse (blake-rouse) wrote :

I would think in the case that MAAS is providing the NTP server it will be all the IPv4 addresses for that DHCP config. When its the users own NTP server, I think we should just strip out the IPv6 addresses and only provide the IPv4 addresses. Then place the other IPv6 address in the dhcpd6 server.

Revision history for this message
Gavin Panella (allenap) wrote :

> I would think in the case that MAAS is providing the NTP server it
> will be all the IPv4 addresses for that DHCP config. When it's the
> user's own NTP server, I think we should just strip out the IPv6
> addresses and only provide the IPv4 addresses.

Okay, agreed.

> Then place the other IPv6 address in the dhcpd6 server.

The ntp-servers option in DHCP is defined by RFC and there's not yet an
IPv6 equivalent so I don't think we can publish IPv6 NTP servers _at
all_ via DHCP.

Revision history for this message
Andres Rodriguez (andreserl) wrote : Re: [Bug 1606499] [NEW] NTP servers must be IPv4 for use with ISC dhcpd

File a bug again de DHCP, add it to the kb board, and we will scalate to
foundations.

On Tuesday, July 26, 2016, Gavin Panella <email address hidden>
wrote:

> > I would think in the case that MAAS is providing the NTP server it
> > will be all the IPv4 addresses for that DHCP config. When it's the
> > user's own NTP server, I think we should just strip out the IPv6
> > addresses and only provide the IPv4 addresses.
>
> Okay, agreed.
>
> > Then place the other IPv6 address in the dhcpd6 server.
>
> The ntp-servers option in DHCP is defined by RFC and there's not yet an
> IPv6 equivalent so I don't think we can publish IPv6 NTP servers _at
> all_ via DHCP.
>
> --
> You received this bug notification because you are subscribed to MAAS.
> https://bugs.launchpad.net/bugs/1606499
>
> Title:
> NTP servers must be IPv4 for use with ISC dhcpd
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/maas/+bug/1606499/+subscriptions
>

--
Andres Rodriguez (RoAkSoAx)
Ubuntu Server Developer
MSc. Telecom & Networking
Systems Engineer

Revision history for this message
Blake Rouse (blake-rouse) wrote :

Does defining ntp-servers in dhcpd6 break? It might support it even though it is not documented.

Revision history for this message
Gavin Panella (allenap) wrote :

> Does defining ntp-servers in dhcpd6 break? It might support it even
> though it is not documented.

For both DHCPv4 and v6, ntp-servers is defined as a list of IPv4
addresses, or hostnames which are resolved by dhcpd into IPv4 addresses.

Andres has pointed out the dhcp6.sntp-servers option which is where we
can put IPv6 NTP servers, and that's also a valid option for both DHCPv4
and DHCPv6. However, it does not accept hostnames.

Revision history for this message
Mike Pontillo (mpontillo) wrote :

Looks like the RFC for NTP in DHCPv6 specifies support for both addresses and hostnames.

https://tools.ietf.org/html/rfc5908

FYI.

Revision history for this message
Andres Rodriguez (andreserl) wrote :

Then let's file bugs for it.

On Tuesday, July 26, 2016, Mike Pontillo <email address hidden>
wrote:

> Looks like the RFC for NTP in DHCPv6 specifies support for both
> addresses and hostnames.
>
> https://tools.ietf.org/html/rfc5908
>
> FYI.
>
> --
> You received this bug notification because you are subscribed to MAAS.
> https://bugs.launchpad.net/bugs/1606499
>
> Title:
> NTP servers must be IPv4 for use with ISC dhcpd
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/maas/+bug/1606499/+subscriptions
>

--
Andres Rodriguez (RoAkSoAx)
Ubuntu Server Developer
MSc. Telecom & Networking
Systems Engineer

Gavin Panella (allenap)
Changed in maas:
assignee: nobody → Gavin Panella (allenap)
status: Triaged → In Progress
MAAS Lander (maas-lander)
Changed in maas:
status: In Progress → Fix Committed
Andres Rodriguez (andreserl)
Changed in maas:
status: Fix Committed → Fix Released
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