diff --git a/Watcher/Controllers/HeartbeatController.cs b/Watcher/Controllers/HeartbeatController.cs
index a30ac9d..10015a9 100644
--- a/Watcher/Controllers/HeartbeatController.cs
+++ b/Watcher/Controllers/HeartbeatController.cs
@@ -10,7 +10,7 @@ using Watcher.ViewModels;
 
 public class HeartbeatDto
 {
-    public int ServerId { get; set; }
+    public string? IpAddress { get; set; }
 }
 
 [ApiController]
@@ -26,9 +26,15 @@ public class HeartbeatController : Controller
     }
 
     [HttpPost("receive")]
-    public async Task<IActionResult> Receive([FromBody] HeartbeatDto heartbeat)
+    public async Task<IActionResult> Receive([FromBody] HeartbeatDto dto)
     {
-        var server = await _context.Servers.FirstOrDefaultAsync(s => s.Id == heartbeat.ServerId);
+        if (string.IsNullOrWhiteSpace(dto.IpAddress))
+        {
+            return BadRequest("Missing IP address.");
+        }
+
+        var server = await _context.Servers
+            .FirstOrDefaultAsync(s => s.IPAddress == dto.IpAddress);
 
         if (server != null)
         {
@@ -37,6 +43,6 @@ public class HeartbeatController : Controller
             return Ok();
         }
 
-        return BadRequest();
+        return NotFound("No matching server found.");
     }
 }