diff --git a/packages/xo-server-transport-nagios/README.md b/packages/xo-server-transport-nagios/README.md
index ccbf1ea8a..300fe1309 100644
--- a/packages/xo-server-transport-nagios/README.md
+++ b/packages/xo-server-transport-nagios/README.md
@@ -12,11 +12,18 @@ Installation of the [npm package](https://npmjs.org/package/xo-server-nagios):
 
 ## Usage
 
-**TODO**
+Like all other xo-server plugins, it can be configured directly via
+the web interface, see [the plugin documentation](https://xen-orchestra.com/docs/plugins.html).
 
 ## Development
 
-```
+### `Xo#sendPassiveCheck( { status, message }) `
+
+This xo method is called to send a passive check to nagios and change the status of a service. 
+It has two parameters:
+- status: it's the service status in Nagios (0: OK | 1: WARNING | 2: CRITICAL).
+- message: it's the status information in Nagios.
+
 # Install dependencies
 > npm install
 
diff --git a/packages/xo-server-transport-nagios/package.json b/packages/xo-server-transport-nagios/package.json
index 53275a2e0..8396d00c5 100644
--- a/packages/xo-server-transport-nagios/package.json
+++ b/packages/xo-server-transport-nagios/package.json
@@ -31,10 +31,14 @@
   "engines": {
     "node": ">=4"
   },
-  "dependencies": {},
+  "dependencies": {
+    "babel-runtime": "^6.18.0",
+    "buffer-crc32": "^0.2.13"
+  },
   "devDependencies": {
     "babel-cli": "^6.18.0",
     "babel-eslint": "^7.1.0",
+    "babel-plugin-transform-runtime": "^6.15.0",
     "babel-preset-latest": "^6.16.0",
     "babel-preset-stage-0": "^6.16.0",
     "cross-env": "^3.1.3",
@@ -55,6 +59,9 @@
     "prepublish": "npm run build"
   },
   "babel": {
+    "plugins": [
+      "transform-runtime"
+    ],
     "presets": [
       "latest",
       "stage-0"
diff --git a/packages/xo-server-transport-nagios/src/index.js b/packages/xo-server-transport-nagios/src/index.js
index ef1e0aa54..98bd0e269 100644
--- a/packages/xo-server-transport-nagios/src/index.js
+++ b/packages/xo-server-transport-nagios/src/index.js
@@ -1,26 +1,164 @@
+import crc32 from 'buffer-crc32'
+import net from 'net'
+import { Buffer } from 'buffer'
+
+// ===================================================================
+
 export const configurationSchema = {
-  foo: {
-    required: true,
-    title: 'Foo',
-    type: 'string'
-  }
+  type: 'object',
+
+  properties: {
+    server: {
+      type: 'string',
+      description: 'The nagios server adress'
+    },
+    port: {
+      type: 'integer',
+      description: 'The NSCA port'
+    },
+    key: {
+      type: 'string',
+      description: 'The encryption key'
+    },
+    host: {
+      type: 'string',
+      description: 'The host name in Nagios'
+    },
+    service: {
+      type: 'string',
+      description: 'The service description in Nagios'
+    }
+  },
+  additionalProperties: false,
+  required: ['server', 'port', 'key', 'host', 'service']
 }
 
+// ===================================================================
+
+function nscaPacketBuilder ({
+  host,
+  iv,
+  message,
+  service,
+  status,
+  timestamp
+}) {
+  // Building NSCA packet
+  const SIZE = 720
+  const packet = new Buffer(SIZE)
+  packet.fill(0)
+  packet.writeInt16BE(VERSION, 0)
+  packet.fill('h', 2, 3)
+  packet.writeUInt32BE(0, 4) // initial 0 for CRC32 value
+  packet.writeUInt32BE(timestamp, 8)
+  packet.writeInt16BE(status, 12)
+  packet.write(host, 14, 77, ENCODING)
+  packet.write(service, 78, 206, ENCODING)
+  packet.write(message, 206, SIZE, ENCODING)
+  packet.writeUInt32BE(crc32.unsigned(packet), 4)
+  return packet
+}
+
+function xor (data, mask) {
+  const dataSize = data.length
+  const maskSize = mask.length
+  const result = new Buffer(dataSize)
+  let j = 0
+  for (let i = 0; i < dataSize; i++) {
+    if (j === maskSize) {
+      j = 0
+    }
+    result[i] = data[i] ^ mask[j]
+    j++
+  }
+  return result
+}
+
+// ===================================================================
+
+export const OK = 0
+export const WARNING = 1
+export const CRITICAL = 2
+
+const VERSION = 3
+const ENCODING = 'binary'
+
 class XoServerNagios {
+
   constructor ({ xo }) {
-    this._xo = xo
+    this._sendPassiveCheck = ::this._sendPassiveCheck
+    this._set = ::xo.defineProperty
+    this._unset = null
+
+   // Defined in configure().
+    this._conf = null
+    this._key = null
   }
 
   configure (configuration) {
-    throw new Error('not implemented')
+    this._conf = configuration
+    this._key = new Buffer(configuration.key, ENCODING)
   }
 
   load () {
-    throw new Error('not implemented')
+    this._unset = this._set('sendPassiveCheck', this._sendPassiveCheck)
   }
 
   unload () {
-    throw new Error('not implemented')
+    this._unset()
+  }
+
+  test () {
+    return this._sendPassiveCheck({
+      message: 'The server-nagios plugin for Xen Orchestra server seems to be working fine, nicely done :)',
+      status: OK
+    })
+  }
+
+  _sendPassiveCheck ({
+    message,
+    status
+  }) {
+    return new Promise((resolve, reject) => {
+      if (/\r|\n/.test(message)) {
+        throw new Error('the message must not contain a line break')
+      }
+
+      const client = new net.Socket()
+
+      client.connect(this._conf.port, this._conf.server, () => {
+        console.log('Successful connection')
+      })
+
+      client.on('data', data => {
+        const timestamp = data.readInt32BE(128)
+        const iv = data.slice(0, 128) // initialization vector
+        const packet = nscaPacketBuilder({
+          ...this._conf,
+          iv,
+          message,
+          status,
+          timestamp
+        })
+
+        // 1) Using xor between the NSCA packet and the initialization vector
+        // 2) Using xor between the result of the first operation and the encryption key
+        const xorPacketBuffer = xor(
+          xor(
+            packet,
+            iv
+          ),
+          this._key
+        )
+
+        client.write(xorPacketBuffer, res => {
+          client.destroy()
+          resolve(res)
+        })
+      })
+
+      client.on('error', reject)
+    })
   }
 }