I have executed
netstat -s on my dedicated server running debian. I'd like to interprete the results because I'm experiencing connectivity problems with TCP. I don't know how to read these results. Can anyone help please ?
The context: It's a public tcp server, with clients from all around the world, most of them use 3G/UMTS networks. The sockets are opened for 1 hour in average. Some tcp links stall for 10-60 seconds, every 10 minutes or so. I'm running a custom java program which is the tcp server.
Here is the output of
netstat -s. Does it show any obvious connectivity problem ?
Ip: 33780786 total packets received 0 forwarded 0 incoming packets discarded 33780059 incoming packets delivered 33577363 requests sent out 1 outgoing packets dropped 1442 reassemblies required 715 packets reassembled ok Icmp: 4675 ICMP messages received 98 input ICMP message failed. ICMP input histogram: destination unreachable: 2901 timeout in transit: 152 echo requests: 1334 echo replies: 226 2109 ICMP messages sent 0 ICMP messages failed ICMP output histogram: destination unreachable: 550 echo request: 225 echo replies: 1334 IcmpMsg: InType0: 226 InType3: 2901 InType8: 1334 InType11: 152 OutType0: 1334 OutType3: 550 OutType8: 225 Tcp: 8752 active connections openings 287296 passive connection openings 58164 failed connection attempts 74065 connection resets received 30 connections established 32997886 segments received 32357425 segments send out 438184 segments retransmited 587 bad segments received. 75868 resets sent Udp: 777245 packets received 550 packets to unknown port received. 0 packet receive errors 779944 packets sent TcpExt: 28674 invalid SYN cookies received 56570 resets received for embryonic SYN_RECV sockets 998 packets pruned from receive queue because of socket buffer overrun 9 ICMP packets dropped because they were out-of-window 27402 packets rejects in established connections because of timestamp 1266543 delayed acks sent 1399 delayed acks further delayed because of locked socket Quick ack mode was activated 143367 times 1556 times the listen queue of a socket overflowed 1556 SYNs to LISTEN sockets dropped 25884635 packets directly queued to recvmsg prequeue. 785180902 bytes directly in process context from backlog 1800599695 bytes directly received in process context from prequeue 2879633 packet headers predicted 7627605 packets header predicted and directly queued to user 3218508 acknowledgments not containing data payload received 14774120 predicted acknowledgments 52 times recovered from packet loss due to fast retransmit 24519 times recovered from packet loss by selective acknowledgements 4 bad SACK blocks received Detected reordering 146 times using FACK Detected reordering 77 times using SACK Detected reordering 2239 times using time stamp 3548 congestion windows fully recovered without slow start 15840 congestion windows partially recovered using Hoe heuristic 8832 congestion windows recovered without slow start by DSACK 127403 congestion windows recovered without slow start after partial ack 12080 TCP data loss events TCPLostRetransmit: 3 179 timeouts after reno fast retransmit 21328 timeouts after SACK recovery 1481 timeouts in loss state 32373 fast retransmits 5349 forward retransmits 26402 retransmits in slow start 230593 other TCP timeouts 4 classic Reno fast retransmits failed 2367 SACK retransmits failed 563 times receiver scheduled too late for direct processing 243774 packets collapsed in receive queue due to low socket buffer 151068 DSACKs sent for old packets 45306 DSACKs sent for out of order packets 238987 DSACKs received 14 DSACKs for out of order packets received 27627 connections reset due to unexpected data 4045 connections reset due to early user close 4992 connections aborted due to timeout IpExt: