A value indicating the maximum number of routers a packet can pass through; it's discarded when it reaches zero.
Short for Time To Live. A field decremented by 1 each time a packet passes through a router. The packet is discarded when it reaches zero, preventing infinite loops. The starting value depends on the OS -- commonly 128 for Windows and 64 for Linux -- so the TTL of a reply packet can hint at the sender's OS.
© 2026 ITBGM