This section describes the global settings that affect
TCP, UDP, and ICMPv6 sessions, in addition to IPv6, NAT64, NAT oversubscription,
jumbo frame size, MTU, accelerated aging, and captive portal authentication.
There is also a setting (Rematch Sessions) that allows you to apply
newly configured security policies to sessions that are already
The first few topics below provide brief summaries of the Transport
Layer of the OSI model, TCP, UDP, and ICMP. For more information
about the protocols, refer to their respective RFCs. The remaining
topics describe the session timeouts and settings.