How to block LSA in ospf on L3 within same area?

[Shireesh_Javkhe]

We have 6 extreme summit L3 460x switches in OSPF. One of them is connected to ISP. We want to block route advertisement of one subnet to ISP.

[Ron_Huygens]

Please note, any change and refresh applied on that policy file will result in temporary withdrawal and then immediate re-advertising of the routes.
Something you should be aware of.