# UDP

> Octelium documentation. Canonical page: <https://octelium.com/docs/octelium/latest/management/core/service/udp>.

*Services* support raw UDP for generic UDP-based applications via the `UDP` mode. Here is an example:

```yaml
kind: Service
metadata:
  name: google-dns
spec:
  port: 53
  # !mark
  mode: UDP
  config:
    upstream:
      url: udp://8.8.8.8:53
```

> **Note:**
>
> For DNS-based applications, it's strongly recommended to use the `DNS` mode
> instead. Read more about the `DNS` mode [here](https://octelium.com/docs/octelium/latest/management/core/service/dns.md).

## Access Control

Just like in `TCP` mode, `UDP` has no application-layer aware information fed to the request context since it operates at layer-4. Here is an example:

```yaml
kind: Service
metadata:
  name: example-svc
spec:
  config:
    upstream:
      url: dns://8.8.8.8
  mode: UDP
  authorization:
    inlinePolicies:
      - spec:
          rules:
            - effect: ALLOW
              condition:
                match: '"group-1" in ctx.user.spec.groups'
```

## Dynamic Configuration

You can use dynamic configuration in order to, for example, route to different upstreams depending on the request's context (read more about dynamic configuration [here](https://octelium.com/docs/octelium/latest/management/core/service/dynamic-config.md)). Here is an example:

```yaml
kind: Service
metadata:
  name: example-svc
spec:
  mode: UDP
  port: 1234
  config:
    upstream:
      url: udp://host-0:9000
  dynamicConfig:
    configs:
      - name: host-1
        upstream:
          url: udp://host-1:9001
      - name: host-2
        upstream:
          url: udp://host-2:9002
    rules:
      - condition:
          match: '"ops" in ctx.user.spec.groups'
        configName: host-1
      - condition:
          match: '"dev" in ctx.user.spec.groups'
        configName: host-2
```

## Visibility

The *Service* emits access logs in real time to the audit collector. Here is an example of a `UDP` *Log*:

```json
{
  "apiVersion": "core/v1",
  "entry": {
    "common": {
      "connectionID": "n8wc-48m1-drfiho77tsir66tzojgma19f-mwq5-c1dd",
      "endedAt": "2025-03-21T22:23:28.959205328Z",
      "isAuthenticated": true,
      "isAuthorized": true,
      "namespaceRef": {
        "apiVersion": "core/v1",
        "kind": "Namespace",
        "name": "default",
        "resourceVersion": "0195b81d-43ec-7ba7-81f7-9b77202b3612",
        "uid": "bff0768e-eec8-4044-a972-9f7af81b79d8"
      },
      "regionRef": {
        "apiVersion": "core/v1",
        "kind": "Region",
        "name": "default",
        "uid": "6e233d12-2fd6-4670-a82d-8c712e1f7374"
      },
      "serviceRef": {
        "apiVersion": "core/v1",
        "kind": "Service",
        "name": "dns-google.default",
        "resourceVersion": "0195bacb-f4d7-77ca-9faf-5c1fec442d7d",
        "uid": "4a2feeb5-6744-4ed7-b1bf-e2ee1aa66da2"
      },
      "sessionRef": {
        "apiVersion": "core/v1",
        "kind": "Session",
        "name": "usr1-3pt93j",
        "resourceVersion": "0195bacb-ed87-76a0-b93b-9b74d7cf122a",
        "uid": "e8bea7be-b858-4457-a8ee-a0cb7f6c91da"
      },
      "startedAt": "2025-03-21T22:22:58.952526275Z",
      "userRef": {
        "apiVersion": "core/v1",
        "kind": "User",
        "name": "usr1",
        "resourceVersion": "0195b821-228d-79b2-92f3-4bb458944f97",
        "uid": "e0f251b2-6952-4a46-a771-2712a45c47f5"
      }
    },
    "info": {
      "udp": {
        "type": "END"
      }
    }
  },
  "kind": "AccessLog",
  "metadata": {
    "actorRef": {
      "apiVersion": "core/v1",
      "kind": "Session",
      "name": "usr1-3pt93j",
      "resourceVersion": "0195bacb-ed87-76a0-b93b-9b74d7cf122a",
      "uid": "e8bea7be-b858-4457-a8ee-a0cb7f6c91da"
    },
    "createdAt": "2025-03-21T22:23:28.959199765Z",
    "id": "hh19-umjd-dt4hhosmolden9btflc2wuzt-wrt9-o2dc",
    "targetRef": {
      "apiVersion": "core/v1",
      "kind": "Service",
      "name": "dns-google.default",
      "resourceVersion": "0195bacb-f4d7-77ca-9faf-5c1fec442d7d",
      "uid": "4a2feeb5-6744-4ed7-b1bf-e2ee1aa66da2"
    }
  }
}
```