Firewall functions: IPTABLES
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is the timeout associated with
CLOSE
state, as defined by RFC 793.
Default value is 10 seconds.
tcp_timeout_close_wait
is the timeout associated with
CLOSE-WAIT
state.
Default value is 30 seconds.
tcp_timeout_established
is the timeout associated with a TCP session active.
Default is 1800 seconds.
tcp_timeout_fin_wait
is the timeout associated with both
FIN-WAIT-1
and
FIN-WAIT-2
state.
Default value is 120 seconds.
tcp_timeout_last_ack
Represents the time-out bound to
LAST-ACK
State.
Default value is 30 seconds.
tcp_timeout_syn_sent
Represents the time-out bound to the
SYN-SENT
state.
Default value is 120 seconds.
tcp_timeout_recv_sent
Represents the time-out associated with
SYN-RECEIVED
State..
The default value is 120 seconds.
UDP connections
UDP connections are commonly
state-less
. This occurs for several reasons: mainly because UDP
connections do not establish a connection and because they do not follow a specific order. The
reception of two UDP datagrams in a certain order, does not necessarily mean that they were sent in
the same order.
From the point of view of the connection tracking, the connection is established in the same
manner as for TCP; however the internal sequence is different. When the first UDP packet is sent,
the entry in the conntrack table becomes:
