Question

帮忙详细解释下linux 的netstat -s 结果显示，越详细越好，谢谢！

TcpExt:
4885761643 SYN cookies sent
4597216785 SYN cookies received
742181693 invalid SYN cookies received
532215970 resets received for embryonic SYN_RECV sockets
1171 packets pruned from receive queue because of socket buffer overrun
240357 ICMP packets dropped because they were out-of-window
8538 ICMP packets dropped because socket was locked
ArpFilter: 0
8958393430 TCP sockets finished time wait in fast timer
7 time wait sockets recycled by time stamp
569209669 TCP sockets finished time wait in slow timer
228891737 passive connections rejected because of time stamp
879267 packets rejects in established connections because of timestamp
2160441260 delayed acks sent
399702 delayed acks further delayed because of locked socket
Quick ack mode was activated 327356426 times
506100 times the listen queue of a socket overflowed
506100 SYNs to LISTEN sockets ignored
22009378110 packets directly queued to recvmsg prequeue.
780194900 packets directly received from backlog
6220660822372 packets directly received from prequeue
9849514523 packets header predicted
21196457682 packets header predicted and directly queued to user
TCPPureAcks: 39482739507
TCPHPAcks: 26731114248
TCPRenoRecovery: 0
TCPSackRecovery: 546525
TCPSACKReneging: 0
TCPFACKReorder: 388
TCPSACKReorder: 0
TCPRenoReorder: 0
TCPTSReorder: 465
TCPFullUndo: 531971
TCPPartialUndo: 575
TCPDSACKUndo: 146532
TCPLossUndo: 1583050
TCPLoss: 12474
TCPLostRetransmit: 319
TCPRenoFailures: 1715240
TCPSackFailures: 236137
TCPLossFailures: 1354349
TCPFastRetrans: 460099
TCPForwardRetrans: 88793
TCPSlowStartRetrans: 41930952
TCPTimeouts: 171484410
TCPRenoRecoveryFail: 0
TCPSackRecoveryFail: 2841
TCPSchedulerFailed: 6586
TCPRcvCollapsed: 71112
TCPDSACKOldSent: 3481399
TCPDSACKOfoSent: 691
TCPDSACKRecv: 3747010
TCPDSACKOfoRecv: 22
TCPAbortOnSyn: 51
TCPAbortOnData: 928575550
TCPAbortOnClose: 1756071170
TCPAbortOnMemory: 0
TCPAbortOnTimeout: 41871415
TCPAbortOnLinger: 0
TCPAbortFailed: 99362
TCPMemoryPressures: 0
TCPSACKDiscard: 0
TCPDSACKIgnoredOld: 2110009
TCPDSACKIgnoredNoUndo: 299544
TCPSpuriousRTOs: 8
TCPMD5NotFound: 0
TCPMD5Unexpected: 0
TCPSackShifted: 1037
TCPSackMerged: 194548
TCPSackShiftFallback: 67620896

Answer 1

tcp/ip的基础知识；不懂的话，我给你翻译出来也是白搭；
大意就是：tcp中请求同步，以及应答等过程；
L1：(数字是序列号)请求同步发送；
L2：收到的同步请求；
L3：无效的请求同步；
L4：重置原始的socket的SYN_RECV状态；
L5：1171个包从接收队列中移除，因为套接字缓冲区溢出了；
L6: 240357 ICMP数据包丢弃，因为它们超出了窗口
L7:8538个因特网控制报文数据包丢弃了；由于socket被锁定了；
L8：地址解析协议过滤器：0