diff --git a/netbox/dcim/constants.py b/netbox/dcim/constants.py
index 5e4311c13..16926081f 100644
--- a/netbox/dcim/constants.py
+++ b/netbox/dcim/constants.py
@@ -32,8 +32,8 @@ CABLE_POSITION_MAX = 1024
 # RearPorts
 #
 
-REARPORT_POSITIONS_MIN = 1
-REARPORT_POSITIONS_MAX = 1024
+PORT_POSITION_MIN = 1
+PORT_POSITION_MAX = 1024
 
 
 #
diff --git a/netbox/dcim/migrations/0221_m2m_port_assignments.py b/netbox/dcim/migrations/0221_m2m_port_assignments.py
new file mode 100644
index 000000000..d6c3710d4
--- /dev/null
+++ b/netbox/dcim/migrations/0221_m2m_port_assignments.py
@@ -0,0 +1,85 @@
+import django.core.validators
+import django.db.models.deletion
+from django.db import migrations
+from django.db import models
+from itertools import islice
+
+
+def chunked(iterable, size):
+    """Yield successive chunks of a given size from an iterator."""
+    iterator = iter(iterable)
+    while chunk := list(islice(iterator, size)):
+        yield chunk
+
+
+def populate_port_assignments(apps, schema_editor):
+    FrontPort = apps.get_model('dcim', 'FrontPort')
+    PortAssignment = apps.get_model('dcim', 'PortAssignment')
+
+    front_ports = FrontPort.objects.iterator(chunk_size=1000)
+
+    def generate_copies():
+        for front_port in front_ports:
+            yield PortAssignment(
+                front_port_id=front_port.pk,
+                front_port_position=1,
+                rear_port_id=front_port.rear_port_id,
+                rear_port_position=front_port.rear_port_position,
+            )
+
+    # Bulk insert in streaming batches
+    for chunk in chunked(generate_copies(), 1000):
+        PortAssignment.objects.bulk_create(chunk, batch_size=1000)
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('dcim', '0220_cable_position'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='PortAssignment',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False)),
+                (
+                    'front_port_position',
+                    models.PositiveSmallIntegerField(
+                        validators=[
+                            django.core.validators.MinValueValidator(1),
+                            django.core.validators.MaxValueValidator(1024),
+                        ]
+                    ),
+                ),
+                (
+                    'rear_port_position',
+                    models.PositiveSmallIntegerField(
+                        validators=[
+                            django.core.validators.MinValueValidator(1),
+                            django.core.validators.MaxValueValidator(1024),
+                        ]
+                    ),
+                ),
+                ('front_port', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='dcim.frontport')),
+                ('rear_port', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='dcim.rearport')),
+            ],
+        ),
+        migrations.AddField(
+            model_name='frontport',
+            name='rear_ports',
+            field=models.ManyToManyField(related_name='front_ports', through='dcim.PortAssignment', to='dcim.rearport'),
+        ),
+        migrations.AddConstraint(
+            model_name='portassignment',
+            constraint=models.UniqueConstraint(
+                fields=('front_port', 'front_port_position'), name='dcim_portassignment_unique_front_port_position'
+            ),
+        ),
+        migrations.AddConstraint(
+            model_name='portassignment',
+            constraint=models.UniqueConstraint(
+                fields=('rear_port', 'rear_port_position'), name='dcim_portassignment_unique_rear_port_position'
+            ),
+        ),
+        migrations.RunPython(code=populate_port_assignments, reverse_code=migrations.RunPython.noop),
+    ]
diff --git a/netbox/dcim/models/device_component_templates.py b/netbox/dcim/models/device_component_templates.py
index 74e624d6c..177da1765 100644
--- a/netbox/dcim/models/device_component_templates.py
+++ b/netbox/dcim/models/device_component_templates.py
@@ -540,8 +540,8 @@ class FrontPortTemplate(ModularComponentTemplateModel):
         verbose_name=_('rear port position'),
         default=1,
         validators=[
-            MinValueValidator(REARPORT_POSITIONS_MIN),
-            MaxValueValidator(REARPORT_POSITIONS_MAX)
+            MinValueValidator(PORT_POSITION_MIN),
+            MaxValueValidator(PORT_POSITION_MAX)
         ]
     )
 
@@ -635,8 +635,8 @@ class RearPortTemplate(ModularComponentTemplateModel):
         verbose_name=_('positions'),
         default=1,
         validators=[
-            MinValueValidator(REARPORT_POSITIONS_MIN),
-            MaxValueValidator(REARPORT_POSITIONS_MAX)
+            MinValueValidator(PORT_POSITION_MIN),
+            MaxValueValidator(PORT_POSITION_MAX)
         ]
     )
 
diff --git a/netbox/dcim/models/device_components.py b/netbox/dcim/models/device_components.py
index 8c9acc48f..3f90963a7 100644
--- a/netbox/dcim/models/device_components.py
+++ b/netbox/dcim/models/device_components.py
@@ -1069,6 +1069,44 @@ class Interface(
 # Pass-through ports
 #
 
+class PortAssignment(models.Model):
+    """
+    Maps a FrontPort & position to a RearPort & position.
+    """
+    front_port = models.ForeignKey(
+        to='dcim.FrontPort',
+        on_delete=models.CASCADE,
+    )
+    front_port_position = models.PositiveSmallIntegerField(
+        validators=(
+            MinValueValidator(PORT_POSITION_MIN),
+            MaxValueValidator(PORT_POSITION_MAX),
+        )
+    )
+    rear_port = models.ForeignKey(
+        to='dcim.RearPort',
+        on_delete=models.CASCADE,
+    )
+    rear_port_position = models.PositiveSmallIntegerField(
+        validators=(
+            MinValueValidator(PORT_POSITION_MIN),
+            MaxValueValidator(PORT_POSITION_MAX),
+        )
+    )
+
+    class Meta:
+        constraints = (
+            models.UniqueConstraint(
+                fields=('front_port', 'front_port_position'),
+                name='%(app_label)s_%(class)s_unique_front_port_position'
+            ),
+            models.UniqueConstraint(
+                fields=('rear_port', 'rear_port_position'),
+                name='%(app_label)s_%(class)s_unique_rear_port_position'
+            ),
+        )
+
+
 class FrontPort(ModularComponentModel, CabledObjectModel, TrackingModelMixin):
     """
     A pass-through port on the front of a Device.
@@ -1082,6 +1120,13 @@ class FrontPort(ModularComponentModel, CabledObjectModel, TrackingModelMixin):
         verbose_name=_('color'),
         blank=True
     )
+    rear_ports = models.ManyToManyField(
+        to='dcim.RearPort',
+        through='dcim.PortAssignment',
+        related_name='front_ports',
+    )
+
+    # Legacy fields
     rear_port = models.ForeignKey(
         to='dcim.RearPort',
         on_delete=models.CASCADE,
@@ -1091,8 +1136,8 @@ class FrontPort(ModularComponentModel, CabledObjectModel, TrackingModelMixin):
         verbose_name=_('rear port position'),
         default=1,
         validators=[
-            MinValueValidator(REARPORT_POSITIONS_MIN),
-            MaxValueValidator(REARPORT_POSITIONS_MAX)
+            MinValueValidator(PORT_POSITION_MIN),
+            MaxValueValidator(PORT_POSITION_MAX)
         ],
         help_text=_('Mapped position on corresponding rear port')
     )
@@ -1157,8 +1202,8 @@ class RearPort(ModularComponentModel, CabledObjectModel, TrackingModelMixin):
         verbose_name=_('positions'),
         default=1,
         validators=[
-            MinValueValidator(REARPORT_POSITIONS_MIN),
-            MaxValueValidator(REARPORT_POSITIONS_MAX)
+            MinValueValidator(PORT_POSITION_MIN),
+            MaxValueValidator(PORT_POSITION_MAX)
         ],
         help_text=_('Number of front ports which may be mapped')
     )