An integer flag indicating whether UDP encapsulation is being used for this remote-access session's IPsec traffic, typically to traverse NAT devices that would otherwise break standard ESP. This is the setting an admin checks when a remote user behind a NAT, most home routers, has connectivity that establishes but then stalls; confirming UDP encapsulation is active for that session rules out NAT traversal as the cause, while it being off for a NAT'd client would explain exactly that symptom. Example: a session showing raUseUDPEncap disabled while raExternalIpAddr resolves to a known NAT'd residential IP range is a strong candidate explanation for that user's intermittent tunnel drops.