Fixes #2724: Limit rear port choices to current device when editing a front port

netbox/dcim/forms.py

@@ -2098,6 +2098,15 @@ class FrontPortForm(BootstrapMixin, forms.ModelForm):
             'device': forms.HiddenInput(),
         }
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        # Limit RearPort choices to the local device
+        if hasattr(self.instance, 'device'):
+            self.fields['rear_port'].queryset = self.fields['rear_port'].queryset.filter(
+                device=self.instance.device
+            )
+
 
 # TODO: Merge with FrontPortTemplateCreateForm to remove duplicate logic
 class FrontPortCreateForm(ComponentForm):