[Kea-users] DHCH NAK through relay

[egor.grijuc at orange.com]

Hello.
My setup is the following:
I have 2 client classes:
"client-classes": [
        {
"name":"LabOltMgm",
"test":"option[82].option[150].hex == 0x6441a000"//100.65.160.0
                },
{
"name":"LabOltData",
"test":"option[82].option[150].hex == 0x5cb58840" //92.181.136.64
                }
    ],

And 2 shared subnets
"shared-networks": [
        {
           "name":"GponManagementSubnets",
           "subnet4": [
{
                    "id": 2,
                    "client-class": "LabOltMgm",
                    "option-data": [{"name": "routers","data": "100.65.160.1"} ],
                    "pools": [{ "pool": "100.65.160.2 - 100.65.160.100"}],
                    "rebind-timer": 600,
                    "renew-timer": 600,
                    "subnet": "100.65.160.0/19",
                    "valid-lifetime": 600
                }
            ]
        },
                {
           "name":"GponDataV4Subnets",
           "subnet4": [
{
                    "id": 3,
                    "client-class": "LabOltData",
                    "option-data": [{"name": "routers","data":"92.181.136.65"},{"name":"domain-name-servers","data":"217.12.120.2"} ],
                    "pools": [{ "pool": "92.181.136.66 - 92.181.136.126"}],
                    "rebind-timer": 600,
                    "renew-timer": 600,
                    "subnet": "92.181.136.64/26",
                    "valid-lifetime": 600
                }
            ]
        }
],

All works fine exept one moment.
When client tries to do renew of ip address, tries to prolongate his lease, kea response with NAK.
The problem is that when client makes simple dhcpdiscover, the packet goes broadcast through the router, router acts like dhcp relay and relays packet to dhcp server kea with added option 82 suboption 150.
But when client makes dhcp renewal-packet goes unicast directly to dhcp server without option 82 suboption 150. As I understand, this causes kea to response with NAK, because packet doesn't match to subnet rule
criteria. In the logs I see message "failed to select a subnet for incoming packet, src 100.65.160.2, type DHCPREQUEST"

Is there a way to configure kea to accept renewal requests if lease already exists and mac address of a client corresponds to stores lease?




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