ATALK-ECHO
AppleTalk Echo Protocol (AEP) is a transport layer protocol designed to test the reachability of network nodes. AEP generates packets to be sent to the network node and is identified in the Type field of a packet as an AEP packet.
Available to all SRX running 12.3X48+
Available to all MX running 20.2R1+
Available to all vSRX running 20.3R1+