inet_peer_maxttl

file: /proc/sys/net/ipv4/inet_peer_maxttl
variable: net.ipv4.inet_peer_maxttl
Official reference

Maximum time-to-live of entries. Unused entries will expire after this period of time if there is no memory pressure on the pool (i.e. when the number of entries in the pool is very small). Measured in seconds.

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