Leaky steering rack

[TuHandy]

I have noticed that there is a leak in my power steering system. I sprayed down the underneath of the car and searched for the leak. I think I have found it on the back side of the steering rack. There seems to be some kind of (vent?) on the back side. Its round and if I remember correctly has a vent cover of some kind. Not sure what it it but it is definately leaking from that area, not the lines.

Is there anything I can do, or is that rack dead, and due for replacement. the car has approx 150,000 on it.

Thanks for the help.