wilmer@nasi:~/tcpwtf$ tcptrace -l nasi.dump 1 arg remaining, starting with 'nasi.dump' Ostermann's tcptrace -- version 6.6.7 -- Thu Nov 4, 2004 93175 packets seen, 93175 TCP packets traced elapsed wallclock time: 0:00:00.407887, 228433 pkts/sec analyzed trace file elapsed time: 0:00:02.446254 TCP connection info: 1 TCP connection traced: TCP connection 1: host a: nasi.dublin.gaast.net:43842 host b: free.hands.com:80 complete conn: yes first packet: Wed Sep 13 10:31:09.054492 2017 last packet: Wed Sep 13 10:31:11.500746 2017 elapsed time: 0:00:02.446254 total packets: 93175 filename: nasi.dump a->b: b->a: total packets: 10744 total packets: 82431 ack pkts sent: 10743 ack pkts sent: 82431 pure acks sent: 10741 pure acks sent: 1 sack pkts sent: 109 sack pkts sent: 0 dsack pkts sent: 0 dsack pkts sent: 0 max sack blks/ack: 1 max sack blks/ack: 0 unique bytes sent: 185 unique bytes sent: 116058283 actual data pkts: 1 actual data pkts: 82428 actual data bytes: 185 actual data bytes: 116058283 rexmt data pkts: 0 rexmt data pkts: 0 rexmt data bytes: 0 rexmt data bytes: 0 zwnd probe pkts: 0 zwnd probe pkts: 0 zwnd probe bytes: 0 zwnd probe bytes: 0 outoforder pkts: 0 outoforder pkts: 95 pushed data pkts: 1 pushed data pkts: 114 SYN/FIN pkts sent: 1/1 SYN/FIN pkts sent: 1/1 req 1323 ws/ts: Y/Y req 1323 ws/ts: Y/Y adv wind scale: 7 adv wind scale: 7 req sack: Y req sack: Y sacks sent: 109 sacks sent: 0 urgent data pkts: 0 pkts urgent data pkts: 0 pkts urgent data bytes: 0 bytes urgent data bytes: 0 bytes mss requested: 1440 bytes mss requested: 1420 bytes max segm size: 185 bytes max segm size: 1408 bytes min segm size: 185 bytes min segm size: 1067 bytes avg segm size: 184 bytes avg segm size: 1407 bytes max win adv: 3145728 bytes max win adv: 29312 bytes min win adv: 28800 bytes min win adv: 29312 bytes zero win adv: 0 times zero win adv: 0 times avg win adv: 2903975 bytes avg win adv: 29312 bytes initial window: 185 bytes initial window: 14080 bytes initial window: 1 pkts initial window: 10 pkts ttl stream length: 185 bytes ttl stream length: 116638379 bytes missed data: 0 bytes missed data: 580096 bytes truncated data: 0 bytes truncated data: 0 bytes truncated packets: 0 pkts truncated packets: 0 pkts data xmit time: 0.000 secs data xmit time: 2.435 secs idletime max: 11.9 ms idletime max: 12.4 ms throughput: 76 Bps throughput: 47443268 Bps wilmer@nasi:~/tcpwtf$ tcptrace -l ruby.dump 1 arg remaining, starting with 'ruby.dump' Ostermann's tcptrace -- version 6.6.7 -- Thu Nov 4, 2004 121241 packets seen, 121237 TCP packets traced elapsed wallclock time: 0:00:00.465948, 260202 pkts/sec analyzed trace file elapsed time: 0:00:08.789509 TCP connection info: 1 TCP connection traced: TCP connection 1: host a: ruby.dublin.gaast.net:46440 host b: free.hands.com:80 complete conn: yes first packet: Wed Sep 13 10:30:52.123367 2017 last packet: Wed Sep 13 10:31:00.912876 2017 elapsed time: 0:00:08.789509 total packets: 121237 filename: ruby.dump a->b: b->a: total packets: 36703 total packets: 84534 ack pkts sent: 36702 ack pkts sent: 84534 pure acks sent: 36700 pure acks sent: 1 Note the receiver sending many more (pure) acks sack pkts sent: 1348 sack pkts sent: 0 dsack pkts sent: 10 dsack pkts sent: 0 max sack blks/ack: 1 max sack blks/ack: 0 unique bytes sent: 214 unique bytes sent: 116638379 actual data pkts: 1 actual data pkts: 84531 actual data bytes: 214 actual data bytes: 119019307 rexmt data pkts: 0 rexmt data pkts: 1691 rexmt data bytes: 0 rexmt data bytes: 2380928 and yay there we go, >2MB of rexmit coming back to it. :-( zwnd probe pkts: 0 zwnd probe pkts: 0 zwnd probe bytes: 0 zwnd probe bytes: 0 outoforder pkts: 0 outoforder pkts: 0 pushed data pkts: 1 pushed data pkts: 478 SYN/FIN pkts sent: 1/1 SYN/FIN pkts sent: 1/1 req 1323 ws/ts: Y/Y req 1323 ws/ts: Y/Y adv wind scale: 7 adv wind scale: 7 req sack: Y req sack: Y sacks sent: 1348 sacks sent: 0 urgent data pkts: 0 pkts urgent data pkts: 0 pkts urgent data bytes: 0 bytes urgent data bytes: 0 bytes mss requested: 1440 bytes mss requested: 1420 bytes max segm size: 214 bytes max segm size: 1408 bytes min segm size: 214 bytes min segm size: 1067 bytes avg segm size: 213 bytes avg segm size: 1407 bytes max win adv: 406016 bytes max win adv: 29312 bytes min win adv: 28800 bytes min win adv: 29312 bytes zero win adv: 0 times zero win adv: 0 times avg win adv: 402805 bytes avg win adv: 29312 bytes initial window: 214 bytes initial window: 9856 bytes initial window: 1 pkts initial window: 7 pkts ttl stream length: 214 bytes ttl stream length: 116638379 bytes missed data: 0 bytes missed data: 0 bytes truncated data: 0 bytes truncated data: 0 bytes truncated packets: 0 pkts truncated packets: 0 pkts data xmit time: 0.000 secs data xmit time: 8.779 secs idletime max: 214.2 ms idletime max: 209.8 ms throughput: 24 Bps throughput: 13270181 Bps