diff --git a/backend/alembic/versions/0006_interface_add_broadcast.py b/backend/alembic/versions/0006_interface_add_broadcast.py
new file mode 100644
index 0000000..381ce57
--- /dev/null
+++ b/backend/alembic/versions/0006_interface_add_broadcast.py
@@ -0,0 +1,21 @@
+"""add broadcast column to interfaces
+
+Revision ID: 0006
+Revises: 0005
+Create Date: 2026-03-01
+"""
+from alembic import op
+import sqlalchemy as sa
+
+revision = "0006"
+down_revision = "0005"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.add_column("interfaces", sa.Column("broadcast", sa.String(64), server_default="''", nullable=False))
+
+
+def downgrade() -> None:
+    op.drop_column("interfaces", "broadcast")
diff --git a/backend/app/models.py b/backend/app/models.py
index 2e344e6..293938a 100644
--- a/backend/app/models.py
+++ b/backend/app/models.py
@@ -60,6 +60,7 @@ class Interface(Base):
     config_id: Mapped[int] = mapped_column(Integer, ForeignKey("configs.id"), nullable=False)
     name: Mapped[str] = mapped_column(String(32), nullable=False)
     zone_id: Mapped[int | None] = mapped_column(Integer, ForeignKey("zones.id"), nullable=True)
+    broadcast: Mapped[str] = mapped_column(String(64), default="")
     options: Mapped[str] = mapped_column(Text, default="")
 
     config: Mapped["Config"] = relationship("Config", back_populates="interfaces")
diff --git a/backend/app/schemas.py b/backend/app/schemas.py
index fa514c4..2281f2c 100644
--- a/backend/app/schemas.py
+++ b/backend/app/schemas.py
@@ -65,12 +65,14 @@ class ZoneOut(BaseModel):
 class InterfaceCreate(BaseModel):
     name: str
     zone_id: Optional[int] = None
+    broadcast: str = ""
     options: str = ""
 
 
 class InterfaceUpdate(BaseModel):
     name: Optional[str] = None
     zone_id: Optional[int] = None
+    broadcast: Optional[str] = None
     options: Optional[str] = None
 
 
@@ -79,6 +81,7 @@ class InterfaceOut(BaseModel):
     config_id: int
     name: str
     zone_id: Optional[int]
+    broadcast: str
     options: str
 
     model_config = {"from_attributes": True}
diff --git a/backend/app/shorewall_generator.py b/backend/app/shorewall_generator.py
index 2ec9df8..8843df8 100644
--- a/backend/app/shorewall_generator.py
+++ b/backend/app/shorewall_generator.py
@@ -26,10 +26,10 @@ class ShorewallGenerator:
         return "".join(lines)
 
     def interfaces(self) -> str:
-        lines = [self._header("interfaces"), "#ZONE".ljust(16) + "INTERFACE".ljust(16) + "OPTIONS\n"]
+        lines = [self._header("interfaces"), "#ZONE".ljust(16) + "INTERFACE".ljust(16) + "BROADCAST".ljust(16) + "OPTIONS\n"]
         for iface in self._config.interfaces:
             zone = iface.zone.name if iface.zone else "-"
-            lines.append(self._col(zone, iface.name, iface.options or "-"))
+            lines.append(self._col(zone, iface.name, iface.broadcast or "-", iface.options or "-"))
         return "".join(lines)
 
     def policy(self) -> str:
diff --git a/frontend/src/routes/ConfigDetail.tsx b/frontend/src/routes/ConfigDetail.tsx
index 2275ef5..96e60f5 100644
--- a/frontend/src/routes/ConfigDetail.tsx
+++ b/frontend/src/routes/ConfigDetail.tsx
@@ -85,11 +85,13 @@ export default function ConfigDetail() {
           label: 'Zone',
           render: (r: AnyEntity) => r['zone_id'] == null ? '-' : (zones.find((z) => z.id === r['zone_id'])?.name ?? String(r['zone_id'])),
         },
+        { key: 'broadcast' as const, label: 'Broadcast' },
         { key: 'options' as const, label: 'Options' },
       ] as Column<AnyEntity>[],
       fields: [
         { name: 'name', label: 'Interface Name', required: true },
         { name: 'zone_id', label: 'Zone', type: 'select' as const, options: [{ value: '', label: '- (no zone)' }, ...zoneOptions] },
+        { name: 'broadcast', label: 'Broadcast' },
         { name: 'options', label: 'Options' },
       ] as FieldDef[],
     },