Aged out

Any traffic that uses UDP or ICMP is seen will have session end reason as aged-out in the traffic log. This is because unlike TCP, there is there is no way for a graceful termination of UDP session and so aged-out is a legitimate session-end reason for UDP (and ICMP) session https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000PMjLCAW

See also

• PAN-OS (Palo Alto): PAN-OS Releases, show vpn, GlobalProtect, GlobalProtect logs, WildFire, show log, show session all, MDM, match, PAN-OS reports, HIP, Zone