diff --git a/handlers/wireguard/analyzer.go b/handlers/wireguard/analyzer.go
new file mode 100644
index 0000000..acab531
--- /dev/null
+++ b/handlers/wireguard/analyzer.go
@@ -0,0 +1,86 @@
+package wireguard
+
+import (
+	"config-lsp/utils"
+	"fmt"
+	"slices"
+
+	protocol "github.com/tliron/glsp/protocol_3_16"
+)
+
+func (p wireguardParser) analyze() []protocol.Diagnostic {
+	diagnostics := []protocol.Diagnostic{}
+
+	diagnostics = append(diagnostics, p.checkForDuplicateProperties()...)
+
+	return diagnostics
+}
+
+func (p wireguardParser) checkForDuplicateProperties() []protocol.Diagnostic {
+	diagnostics := []protocol.Diagnostic{}
+
+	for _, section := range p.Sections {
+		diagnostics = append(diagnostics, section.analyDuplicateProperties()...)
+	}
+
+	return diagnostics
+}
+
+func (p wireguardSection) analyDuplicateProperties() []protocol.Diagnostic {
+	diagnostics := []protocol.Diagnostic{}
+
+	existingProperties := make(map[string]uint32)
+
+	lines := utils.KeysOfMap(p.Properties)
+	slices.Sort(lines)
+
+	for _, currentLineNumber := range lines {
+		property := p.Properties[currentLineNumber]
+		var skipCheck = false
+
+		if p.Name != nil {
+			switch *p.Name {
+			case "Interface":
+				if _, found := interfaceAllowedDuplicateFields[property.Key.Name]; found {
+					skipCheck = true
+				}
+			case "Peer":
+				if _, found := peerAllowedDuplicateFields[property.Key.Name]; found {
+					skipCheck = true
+				}
+			}
+		}
+
+		if skipCheck {
+			continue
+		}
+
+		if existingLineNumber, found := existingProperties[property.Key.Name]; found {
+			severity := protocol.DiagnosticSeverityError
+			diagnostics = append(diagnostics, protocol.Diagnostic{
+				Message:  fmt.Sprintf("Property '%s' is already defined on line %d", property.Key.Name, existingLineNumber+1),
+				Severity: &severity,
+				Range: protocol.Range{
+					Start: protocol.Position{
+						Line:      currentLineNumber,
+						Character: 0,
+					},
+					End: protocol.Position{
+						Line:      currentLineNumber,
+						Character: 99999,
+					},
+				},
+			})
+		} else {
+			existingProperties[property.Key.Name] = currentLineNumber
+		}
+	}
+
+	return diagnostics
+}
+
+func (p wireguardSection) analyzeInterfaceSection() []protocol.Diagnostic {
+	diagnostics := []protocol.Diagnostic{}
+
+	return diagnostics
+}
diff --git a/handlers/wireguard/text-document-did-change.go b/handlers/wireguard/text-document-did-change.go
index 04b048d..aa4d3d6 100644
--- a/handlers/wireguard/text-document-did-change.go
+++ b/handlers/wireguard/text-document-did-change.go
@@ -30,7 +30,7 @@ func TextDocumentDidChange(
 		)...)
 	}
 
-	// diagnostics = append(diagnostics, parser.AnalyzeValues()...)
+	diagnostics = append(diagnostics, parser.analyze()...)
 
 	if len(diagnostics) > 0 {
 		common.SendDiagnostics(context, params.TextDocument.URI, diagnostics)