The announcement is real; the follow-through is not
An Irish Setter will generally tell you someone has arrived. The breed is alert, interested in the household's comings and goings, and perfectly willing to bark at a knock, a gate, or footsteps on the path — so as a doorbell with fur, a setter performs. A watchdog, though, is supposed to change how the stranger behaves, and here the performance collapses. The setter who has just announced your visitor will greet that visitor as a long-lost friend the instant the door opens, and anyone with passing knowledge of dogs can see there is no threat behind the noise. If the honest answer matters to your decision, buy your security elsewhere and your setter for joy.
Why there is no guard in this breed
It was bred out on purpose, over a long time. Irish Setters were developed as gundogs for shooting parties, where the dog travelled, was handled by beaters, keepers, and fellow guns, and was expected to be equable with every stranger in the field. Breeders selected against suspicion and possession-guarding for generations, and the modern standard treats shyness itself as a fault. Resource guarding and territorial behaviour are correspondingly rare — a setter is more likely to bring a burglar a toy than to dispute the silverware. You cannot train a guarding instinct into a dog whose temperament was engineered in the opposite direction, and it would be unkind to try.
What owners actually experience
The pattern most households report is a dog who barks at the boundary and celebrates at the threshold. Some setters bark more than others — an under-exercised, bored setter barks at the window for entertainment, which is an exercise problem wearing a watchdog costume — but even the keenest setter's bark is commentary, not warning. Owners who wanted a deterrent sometimes feel misled by the size: a tall, deep-chested dog looks like security. It is worth remembering that deterrence-by-appearance fails exactly when tested, and planning around the dog's real nature — sociable to a fault — is the safer basis for your household's decisions.
The security implication nobody mentions
A dog this friendly to strangers carries one specific household risk worth planning for: he will go with people. A setter is happy to trot out of an open gate with a caller, accompany a delivery driver down the path out of pure social enthusiasm, or load himself into an interesting vehicle. So the practical security work for a setter owner is inverted — not keeping strangers out, but keeping the dog in: self-closing gates, an airlock routine at the front door, and never assuming the dog's good nature will keep him home. Check fencing with a setter's athleticism in mind, too; a bored setter can clear or dig under a token barrier when the world outside is being so interesting.
Cover the risk that actually exists
Judge the breed fairly: nobody who knows setters chooses one as a watchdog, and the breed loses nothing by the verdict — its talents are companionship, sport, and an infectious delight in people. Your household security should rest on locks, lights, and alarms, with the dog as a noisy bonus. Guard against that same openness instead: should he trot out behind a caller or slip a gate left ajar, a Lost Pet Alert System alert in KinsLe costs nothing through his profile, pins him to a map display, and gives whoever finds him a direct message route back to you — he will very likely be charming them as they use it.