netstat †ルーティング表示 †# netstat -rn Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 192.168.3.0 172.16.0.1 255.255.255.0 UG 0 0 0 br0 192.168.2.0 172.16.0.1 255.255.255.0 UG 0 0 0 br0 192.168.1.0 172.16.0.1 255.255.255.0 UG 0 0 0 br0 192.168.4.0 172.16.0.1 255.255.255.0 UG 0 0 0 br0 172.19.0.0 0.0.0.0 255.255.0.0 U 0 0 0 br0 127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo 0.0.0.0 172.19.0.254 0.0.0.0 UG 0 0 0 br0 ※Ifaceがbr0になっているのはkvmを使用しているため。~ TIPS: 上記1行目であれば、
TCPステータス表示 †# netstat -an Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 127.0.0.1:5901 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:60717 0.0.0.0:* LISTEN (省略) tcp 0 0 172.16.0.164:34000 172.16.0.143:22 ESTABLISHED tcp 0 0 172.16.0.164:22 172.16.0.79:3694 ESTABLISHED (省略) TIPS: 参考:http://www.linux.or.jp/JM/html/net-tools/man8/netstat.8.html netstatの結果で使用Listenポートが分かったと思うが、実際にそれが何に使われているポートなのかは不明なことが多い。その場合は通信ポートを追うことが出来るので調査は可能。 プロトコルレベルでの統計情報 †# netstat -s Ip: 1220411720 total packets received 0 forwarded 0 incoming packets discarded 1220411720 incoming packets delivered 970661029 requests sent out Icmp: 84455 ICMP messages received 0 input ICMP message failed. ICMP input histogram: echo requests: 84455 84476 ICMP messages sent 0 ICMP messages failed ICMP output histogram: destination unreachable: 17 echo request: 4 echo replies: 84455 IcmpMsg: InType8: 84455 OutType0: 84455 OutType3: 17 OutType8: 4 Tcp: 1437745 active connections openings 1814627 passive connection openings 1247203 failed connection attempts 64549 connection resets received 72 connections established 1220025202 segments received 965158827 segments send out 5146849 segments retransmited 0 bad segments received. 68773 resets sent Udp: 265443 packets received 17 packets to unknown port received. 82 packet receive errors 270877 packets sent RcvbufErrors: 82 UdpLite: TcpExt: 9873 invalid SYN cookies received 1246216 resets received for embryonic SYN_RECV sockets 1202 packets pruned from receive queue because of socket buffer overrun 2468758 TCP sockets finished time wait in fast timer 9743 time wait sockets recycled by time stamp 2834036 delayed acks sent 1496 delayed acks further delayed because of locked socket Quick ack mode was activated 57796 times 6340 times the listen queue of a socket overflowed 6340 SYNs to LISTEN sockets ignored 316 packets directly queued to recvmsg prequeue. 3848 packets directly received from backlog 62347 packets directly received from prequeue 788669778 packets header predicted 145 packets header predicted and directly queued to user 352635722 acknowledgments not containing data received 344667303 predicted acknowledgments 497341 times recovered from packet loss due to fast retransmit 930913 times recovered from packet loss due to SACK data Detected reordering 45806 times using reno fast retransmit TCPDSACKUndo: 50 108097 congestion windows recovered after partial ack 687871 TCP data loss events TCPLostRetransmit: 11137 144611 timeouts after reno fast retransmit 136373 timeouts after SACK recovery 13385 timeouts in loss state 1662743 fast retransmits 183030 forward retransmits 1647722 retransmits in slow start 958417 other TCP timeouts TCPRenoRecoveryFail: 355365 6185 sack retransmits failed 55656 packets collapsed in receive queue due to low socket buffer 179821 DSACKs sent for old packets 3639 DSACKs sent for out of order packets 26169 DSACKs received 214 connections reset due to unexpected data 132 connections reset due to early user close 1652 connections aborted due to timeout TCPDSACKIgnoredNoUndo: 978 TCPSpuriousRTOs: 712 TCPSackShifted: 146638 TCPSackMerged: 1803104 TCPSackShiftFallback: 2011909 IpExt: InBcastPkts: 36521 InOctets: 717648600698 OutOctets: 761319460423 InBcastOctets: 4337417 かなりのボリュームがあるので、それぞれにどんな意味があるかは説明できないが、困ったときには使えるオプション。 実体験で一番役に立ったのは、 これはサーバが受け取れなかったセッションの数。 詳しくは |