A network engineer needs to deploy 802.1x using Cisco ISE in a wired network environment where thin clients download their system image upon bootup using PXE. For which mode must the switch ports be…

Closed mode (or `authentication host-mode single-host` with `dot1x control-direction in`) completely blocks network access until successful 802.1x authentication, which would prevent PXE boot.

Restricted mode provides limited access to a guest VLAN after failed authentication, not initial access for pre-authentication services.

Monitor mode is typically used for passively monitoring authentication attempts without enforcing 802.1x, which does not provide the necessary control or security post-PXE.

Low-impact mode (also known as open authentication or monitor mode in some contexts) allows endpoints to have limited network access before full 802.1x authentication. This is crucial for services like PXE boot, where the client needs network connectivity to obtain an IP address and download an image before it can fully authenticate.