[Kea-users] DHCP6 subnet select fails. Basic config

Tim Howe tim.h at bendtel.com
Wed Jan 10 20:18:24 UTC 2018


Any clue is much appreciated.  I haven't actually managed a single
working config yet (have v4 working fine).

I'm trying to get just the most stripped down basic DHCP6 functions
working ATM.

There is only one subnet configured, and I'm not trying to select it in
any fancy ways yet, but it seems the server doesn't know to use it for
the DHCP requests(?)

I have a router running route advertisement for the subnet and the M
flag configured.
I have the DHCP server running on the same subnet.

I've tested turning on and off autonomous flag for the rtradv server.
I have also tested it with and without a local IP address in that
subnet set on the interface.

For reference, here's the route advertisement config on the Juniper ACX:

router-advertisement {
    interface xe-0/0/4.1600 {
        managed-configuration;
        prefix 2607:fda0:101:1601::/64;
    }
}

The Kea config for DHCPv6 is pretty basic.  I include it all here for
completeness.

"Dhcp6": {
    "interfaces-config": {
        "interfaces": [ "igb2.1600" ]
    },
    "control-socket": {
        "socket-type": "unix",
        "socket-name": "/tmp/kea-dhcp6-ctrl.sock"
    },
    "lease-database": {
        "type": "memfile"
    },
    "expired-leases-processing": {
        "reclaim-timer-wait-time": 10,
        "flush-reclaimed-timer-wait-time": 25,
        "hold-reclaimed-time": 3600,
        "max-reclaim-leases": 100,
        "max-reclaim-time": 250,
        "unwarned-reclaim-cycles": 5
    },
    "renew-timer": 1000,
    "rebind-timer": 2000,
    "preferred-lifetime": 3000,
    "valid-lifetime": 4000,
         
    "option-data": [
        {
            "name": "dns-servers",
            "data": "2607:fda0:30::1eaf, 2607:fda0:30:1::107a"
        }
    ],
    "subnet6": [
        {
            "subnet": "2607:fda0:101:1601::/64",
            "pools": [ { "pool": "2607:fda0:101:1601:4::/80" } ]
        }
    ]
},

	Full debug looks like this...  I don't see any indication that
the device is aware of the subnet it should be using (but I don't know
if I would).  I have tested that the rtradv server is working.

2018-01-10 11:57:13.007 DEBUG [kea-dhcp6.packets/66853] DHCP6_BUFFER_RECEIVED received buffer from fe80::1e74:dff:fe4b:cd76:546 to ff02::1:2:0 over interface igb2.1600
2018-01-10 11:57:13.008 DEBUG [kea-dhcp6.options/66853] DHCP6_BUFFER_UNPACK parsing buffer received from fe80::1e74:dff:fe4b:cd76 to ff02::1:2 over interface igb2.1600
2018-01-10 11:57:13.008 DEBUG [kea-dhcp6.packets/66853] DHCP6_PACKET_RECEIVED duid=[00:03:00:01:1c:74:0d:4b:cd:76], tid=0x57be92: SOLICIT (type 1) received from fe80::1e74:dff:fe4b:cd76 to ff02::1:2 on interface igb2.1600
2018-01-10 11:57:13.008 DEBUG [kea-dhcp6.packets/66853] DHCP6_QUERY_DATA duid=[00:03:00:01:1c:74:0d:4b:cd:76], tid=0x57be92, packet details: localAddr=[ff02::1:2]:0 remoteAddr=[fe80::1e74:dff:fe4b:cd76]:546
msgtype=1(SOLICIT), transid=0x57be92
type=00001, len=00010: 00:03:00:01:1c:74:0d:4b:cd:76
type=00003(IA_NA), len=00012: iaid=1, t1=0, t2=0
type=00008, len=00002: 0 (uint16)
type=00025(IA_PD), len=00012: iaid=0, t1=0, t2=0
1 relay(s):
relay[0]: msg-type=12(RELAY_FORWARD), hop-count=0,
link-address=::, peer-address=fe80::1e74:dff:fe4b:cd76, 1 option(s)
type=00018, len=00007: 33:2f:32:2f:31:2f:31

2018-01-10 11:57:13.008 DEBUG [kea-dhcp6.packets/66853] DHCP6_SUBNET_SELECTION_FAILED duid=[00:03:00:01:1c:74:0d:4b:cd:76], tid=0x57be92: failed to select subnet for the client
2018-01-10 11:57:13.008 DEBUG [kea-dhcp6.leases/66853] DHCP6_PROCESS_IA_NA_REQUEST duid=[00:03:00:01:1c:74:0d:4b:cd:76], tid=0x57be92: server is processing IA_NA option with iaid=1 and hint=(no hint)
2018-01-10 11:57:13.008 DEBUG [kea-dhcp6.options/66853] DHCP6_ADD_STATUS_CODE_FOR_IA duid=[00:03:00:01:1c:74:0d:4b:cd:76], tid=0x57be92: adding Status Code to IA with iaid=1: NoAddrsAvail(2) "Server could not select subnet for this client"
2018-01-10 11:57:13.008 DEBUG [kea-dhcp6.leases/66853] DHCP6_PROCESS_IA_PD_REQUEST duid=[00:03:00:01:1c:74:0d:4b:cd:76], tid=0x57be92: server is processing IA_PD option with iaid=0 and hint=(no hint)
2018-01-10 11:57:13.008 DEBUG [kea-dhcp6.options/66853] DHCP6_ADD_STATUS_CODE_FOR_IA duid=[00:03:00:01:1c:74:0d:4b:cd:76], tid=0x57be92: adding Status Code to IA with iaid=0: NoPrefixAvail(6) "Sorry, no subnet available."
2018-01-10 11:57:13.008 DEBUG [kea-dhcp6.packets/66853] DHCP6_RESPONSE_DATA responding with packet type 2 data is localAddr=[ff02::1:2]:547 remoteAddr=[fe80::1e74:dff:fe4b:cd76]:547
msgtype=2(ADVERTISE), transid=0x57be92
type=00001, len=00010: 00:03:00:01:1c:74:0d:4b:cd:76
type=00002, len=00014: 00:01:00:87:21:d9:8c:b2:ac:1f:6b:22:56:3a
type=00003(IA_NA), len=00064: iaid=1, t1=0, t2=0,
options:
  type=00013, len=00048: NoAddrsAvail(2) "Server could not select subnet for this client"
type=00025(IA_PD), len=00045: iaid=0, t1=0, t2=0,
options:
  type=00013, len=00029: NoPrefixAvail(6) "Sorry, no subnet available."
1 relay(s):
relay[0]: msg-type=13(RELAY_REPLY), hop-count=0,
link-address=::, peer-address=fe80::1e74:dff:fe4b:cd76, 1 option(s)
type=00018, len=00007: 33:2f:32:2f:31:2f:31



--TimH

P.S. Yes, I realize I am not obfuscating the IPs.



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