[Kea-users] [kea-dev] Reverse DNS update

[tach yon]

________________________________
From: Thomas Markwalder <tmark at isc.org>
Sent: 10 June 2016 11:37
To: tach yon; kea-users at lists.isc.org
Subject: Re: [kea-dev] Reverse DNS update

On 6/2/16 11:11 AM, Thomas Markwalder wrote:
:

Hi Tomas,

I cleared the logs and renewed the address on my test machine to hopefully capture only the related events. Please find the logs attached. Apologies for the format of this message, this email web client is being very stupid :(

With thanks,
Lewis


Hi Lewis:

Looking at the kea-dhcp4.log, you'll see this:

2016-06-02 15:05:35.953 DEBUG [kea-dhcp4.packets/35454] DHCP4_QUERY_DATA [hwtype=1 00:50:56:9d:0f:1f], cid=[01:00:50:56:9d:0f:1f], tid=0x3765bcd1, packet details: local_address=255.255.255.255:67, remote_adress=0.0.0.0:68, msg_type=DHCPREQUEST (3), transid=0x3765bcd1,
options:
  type=012, len=007: "windhcp" (string)
  type=050, len=004: 10.12.30.150 (ipv4-address)
  type=053, len=001: 3 (uint8)
  type=054, len=004: 10.12.30.6 (ipv4-address)
  type=055, len=012: 1(uint8) 15(uint8) 3(uint8) 6(uint8) 44(uint8) 46(uint8) 47(uint8) 31(uint8) 33(uint8) 121(uint8) 249(uint8) 43(uint8)
  type=060, len=008: "MSFT 5.0" (string)
  type=061, len=007: 01:00:50:56:9d:0f:1f
  type=81 (CLIENT_FQDN), flags: (N=0, E=0, O=0, S=0), domain-name='windhcp' (partial)


The FQDN flags being sent up by your Client, specify N and S as 0, which translates to "Client wants to do forward updates, server should do reverse updates".   Look at Table 7.4 in the Kea Admin guide.  You have two options:

1. If you have control over your client you can change these flags to be N=0, S=1 ... this requests the server to do both Forward and Reverse updates.

2. If you cannot control the client, then you can use the parameter override-client-update. When this parameter is true, kea-dhcp4 will disregard requests for client delegation and generate a DDNS request to update both forward and reverse DNS data:

"Dhcp4": {
    "dhcp-ddns": {
        "override-client-update": true,
        ...
    },
    ...
}

Looking kea-ddns.log, it receives the request from kea-dhcp4 but drops as it  does not request forward updates (due to the client flags) and reverse updates are not enabled (no reverse domains), so it correctly drops the request.

Once you've addressed the flag issue, you should be on your way.

Thomas

ISC Software Engineering



Hi Lewis:

I'm just following up to see if you've gotten things working.   I've also cc'd this email to our user list: kea-users at lists.isc.org<mailto:kea-users at lists.isc.org>.   Using this email lets you look for answers and share ideas with our growing Kea user community.   Our users are a creative, thoughtful group eager to help and learn from each other.

Regards,

Thomas Markwalder

ISC Software Engineering



Hi Thomas,


I tried using the override-client-update option. My test DNS server happily receives dynamic updates now, thanks muchly!


Kind regards,

Lewis
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