Refer to the exhibit.

Refer to the exhibit. AS 65517 is running OSPF within the core. BGP is running between all four autonomous systems, interconnecting several ISPs that provide intranet and extranet services. All of the PE routers are connected, and eBGP peering relationships have been established. A network engineer also configured an iBGP peering between PE3 and P1, and the peering is up. However, P1 cannot reach routes outside of AS 65517. Which action must the engineer take so that P1 reaches external routes?)