@yage , thanks! Here is the tcp dump:
tcp:
0 packet sent
0 data packet (0 byte)
0 data packet (0 byte) retransmitted
0 resend initiated by MTU discovery
0 ack-only packet (0 delayed)
0 URG only packet
0 window probe packet
0 window update packet
0 control packet
0 data packet sent after flow control
0 challenge ACK sent due to unexpected SYN
0 challenge ACK sent due to unexpected RST
0 checksummed in software
0 segment (0 byte) over IPv4
0 segment (0 byte) over IPv6
0 packet received
0 ack (for 0 byte)
0 duplicate ack
0 ack for unsent data
0 packet (0 byte) received in-sequence
0 completely duplicate packet (0 byte)
0 old duplicate packet
0 received packet dropped due to low memory
0 packet with some dup. data (0 byte duped)
0 out-of-order packet (0 byte)
0 packet (0 byte) of data after window
0 window probe
0 window update packet
0 packet recovered after loss
0 packet received after close
0 bad reset
0 discarded for bad checksum
0 checksummed in software
0 segment (0 byte) over IPv4
0 segment (0 byte) over IPv6
0 discarded for bad header offset field
0 discarded because packet too short
0 connection request
0 connection accept
0 bad connection attempt
0 listen queue overflow
0 connection established (including accepts)
0 connection closed (including 0 drop)
0 connection updated cached RTT on close
0 connection updated cached RTT variance on close
0 connection updated cached ssthresh on close
0 connection initialized RTT from route cache
0 connection initialized RTT variance from route cache
0 connection initialized ssthresh from route cache
0 embryonic connection dropped
0 segment updated rtt (of 0 attempt)
0 retransmit timeout
0 connection dropped by rexmit timeout
0 connection dropped after retransmitting FIN
0 unnecessary packet retransmissions
0 persist timeout
0 connection dropped by persist timeout
0 keepalive timeout
0 keepalive probe sent
0 connection dropped by keepalive
0 connection dropped by keepalive offload
0 correct ACK header prediction
0 correct data packet header prediction
0 SACK recovery episode
0 segment rexmit in SACK recovery episodes
0 byte rexmit in SACK recovery episodes
0 SACK option (SACK blocks) received
0 SACK option (SACK blocks) sent
0 SACK scoreboard overflow
0 limited transmit done
0 early retransmit done
0 time cumulative ack advanced along with SACK
0 probe timeout
0 time retransmit timeout triggered after probe
0 time probe packets were sent for an interface
0 time couldn't send probe packets for an interface
0 time fast recovery after tail loss
0 time recovered last packet
0 SACK based rescue retransmit
0 client connection attempted to negotiate ECN
0 client connection successfully negotiated ECN
0 time graceful fallback to Non-ECN connection
0 time lost ECN negotiating SYN, followed by retransmission
0 server connection attempted to negotiate ECN
0 server connection successfully negotiated ECN
0 time lost ECN negotiating SYN-ACK, followed by retransmission
0 time received congestion experienced (CE) notification
0 time CWR was sent in response to ECE
0 time sent ECE notification
0 connection received CE atleast once
0 connection received ECE atleast once
0 connection using ECN have seen packet loss but no CE
0 connection using ECN have seen packet loss and CE
0 connection using ECN received CE but no packet loss
0 connection fell back to non-ECN due to SYN-loss
0 connection fell back to non-ECN due to reordering
0 connection fell back to non-ECN due to excessive CE-markings
0 connection fell back caused by connection drop due to RST
0 connection fell back due to drop after multiple retransmits
0 connection fell back due to RST after SYN
0 time packet reordering was detected on a connection
0 time transmitted packets were reordered
0 time fast recovery was delayed to handle reordering
0 time retransmission was avoided by delaying recovery
0 retransmission not needed
0 retransmission due to tail loss
0 time DSACK option was sent
0 time DSACK option was received
0 time DSACK was disabled on a connection
0 time recovered from bad retransmission using DSACK
0 time ignored DSACK due to ack loss
0 time ignored old DSACK options
0 time PMTU Blackhole detection, size reverted
0 connection were dropped after long sleep
0 connection had stretch ack algorithm disabled
0 time a TFO-cookie has been announced
0 SYN with data and a valid TFO-cookie have been received
0 SYN with TFO-cookie-request received
0 time an invalid TFO-cookie has been received
0 time we requested a TFO-cookie
0 time the peer announced a TFO-cookie
0 time we combined SYN with data and a TFO-cookie
0 time our SYN with data has been acknowledged
0 time a connection-attempt with TFO fell back to regular TCP
0 time a TFO-connection blackhole'd
0 time a TFO-cookie we sent was wrong
0 time did not received a TFO-cookie we asked for
0 time TFO got disabled due to heuristicsn
0 time TFO got blackholed in the sending direction
0 time maximum segment size was changed to default
0 time maximum segment size was changed to medium
0 time maximum segment size was changed to low
0 timer drift less or equal to 1 ms
0 timer drift less or equal to 10 ms
0 timer drift less or equal to 20 ms
0 timer drift less or equal to 50 ms
0 timer drift less or equal to 100 ms
0 timer drift less or equal to 200 ms
0 timer drift less or equal to 500 ms
0 timer drift less or equal to 1000 ms
0 timer drift greater than to 1000 ms
All zeroes. Is that good or bad?? 😳