Keepalive v TCP Idle timeout

as Kevin mentioned, tcp connection will be reset when idle timeout exceeds.

e.g.

// config

root@(B6900-R69-S40)(cfg-sync Standalone)(Active)(/Common)(tmos) list ltm virtual bar
ltm virtual bar {
    destination 100.100.100.41:23
    ip-protocol tcp
    mask 255.255.255.255
    pool foo
    profiles {
        tcp {
            context serverside
        }
        tcp-timeout-10s {
            context clientside
        }
    }
    source 0.0.0.0/0
    source-address-translation {
        type automap
    }
    vs-index 4
}
root@(B6900-R69-S40)(cfg-sync Standalone)(Active)(/Common)(tmos) list ltm pool foo
ltm pool foo {
    members {
        200.200.200.101:23 {
            address 200.200.200.101
        }
    }
}
root@(B6900-R69-S40)(cfg-sync Standalone)(Active)(/Common)(tmos) list ltm profile tcp tcp-timeout-10s
ltm profile tcp tcp-timeout-10s {
    app-service none
    idle-timeout 10
    keep-alive-interval 1800
}

// clientside (client ip is 100.100.100.3)

[root@B6900-R69-S40:Active:Standalone] config  tcpdump -nni 0.0:nnn host 100.100.100.41 and port 23
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on 0.0:nnn, link-type EN10MB (Ethernet), capture size 96 bytes
...snipped...
16:23:17.334177 IP 100.100.100.41.23 > 100.100.100.3.40421: P 225:245(20) ack 99 win 4478 
16:23:17.334524 IP 100.100.100.3.40421 > 100.100.100.41.23: . ack 245 win 5840 

16:23:28.888849 IP 100.100.100.41.23 > 100.100.100.3.40421: R 245:245(0) ack 99 win 4478

// serverside (snat automap ip is 200.200.200.40)

[root@B6900-R69-S40:Active:Standalone] config  tcpdump -nni 0.0:nnn -s0 host 200.200.200.101 and port 23
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on 0.0:nnn, link-type EN10MB (Ethernet), capture size 65535 bytes
...snipped...
16:23:17.334169 IP 200.200.200.101.23 > 200.200.200.40.40421: P 225:245(20) ack 99 win 5792  in slot1/tmm0 lis=/Common/bar flowtype=128 flowid=5700010E3700 peerid=5700010E2C00 conflags=8124 inslot=4 inport=0 haunit=0 priority=3 peerremote=00000000:00000000:0000FFFF:64646403 peerlocal=00000000:00000000:0000FFFF:64646429 remoteport=40421 localport=23 proto=6 vlan=1149
16:23:17.334180 IP 200.200.200.40.40421 > 200.200.200.101.23: . ack 245 win 4624  out slot1/tmm0 lis=/Common/bar flowtype=128 flowid=5700010E3700 peerid=5700010E2C00 conflags=8124 inslot=4 inport=0 haunit=1 priority=3 peerremote=00000000:00000000:0000FFFF:64646403 peerlocal=00000000:00000000:0000FFFF:64646429 remoteport=40421 localport=23 proto=6 vlan=1149

16:23:28.888819 IP 200.200.200.40.40421 > 200.200.200.101.23: R 99:99(0) ack 245 win 4624 out slot1/tmm0 lis=/Common/bar flowtype=128 flowid=5700010E3700 peerid=5700010E2C00 conflags=80812C inslot=4 inport=0 haunit=1 priority=3 rst_cause="[0x1ac6d2a:848] {peer} Flow expired (sweeper) (idle timeout" peerremote=00000000:00000000:0000FFFF:64646403 peerlocal=00000000:00000000:0000FFFF:64646429 remoteport=40421 localport=23 proto=6 vlan=1149