要显示网络状态信息,例如有关网络接口状态、路由表和各种协议的统计信息,请使用 netstat 命令。
$ netstat [-i] [-r] [-s] |
显示 TCP/IP 接口的状态
显示 IP 路由表
显示 UDP、TCP、ICMP 和 IGMP 协议的统计信息
有关更多信息,请参见 netstat(1M)。
以下示例显示 netstat -i 命令的输出,其中显示了用于 TCP/IP 流量的接口的状态。
$ netstat -i Name Mtu Net/Dest Address Ipkts Ierrs Opkts Oerrs Collis Queue lo0 8232 software localhost 1280 0 1280 0 0 0 eri0 1500 loopback venus 1628480 0 347070 16 39354 0 |
此输出显示了机器在每个接口中传输和接收的包数。对于具有活动网络通信流量的机器而言,Ipkts 和 Opkts 都应持续增加。
将冲突计数 (Collis) 除以传出的包数 (Opkts),以计算网络冲突率。在上一示例中,冲突率为 11%。如果网络范围内的冲突率大于 5% 至 10 %,则表示可能存在问题。
将输入错误数除以输入包的总数 (Ierrs/Ipkts),以计算输入包的错误率。输出包的错误率等于输出错误数除以输出包的总数 (Oerrs/Opkts)。如果输入错误率较高(高于 0.25%)则主机可能在删除包。
以下示例显示 netstat -s 命令的输出,其中显示了 UDP、TCP、ICMP 和 IGMP 协议的按协议的统计信息。
UDP udpInDatagrams =196543 udpInErrors = 0 udpOutDatagrams =187820 TCP tcpRtoAlgorithm = 4 tcpRtoMin = 200 tcpRtoMax = 60000 tcpMaxConn = -1 tcpActiveOpens = 26952 tcpPassiveOpens = 420 tcpAttemptFails = 1133 tcpEstabResets = 9 tcpCurrEstab = 31 tcpOutSegs =3957636 tcpOutDataSegs =2731494 tcpOutDataBytes =1865269594 tcpRetransSegs = 36186 tcpRetransBytes =3762520 tcpOutAck =1225849 tcpOutAckDelayed =165044 tcpOutUrg = 7 tcpOutWinUpdate = 315 tcpOutWinProbe = 0 tcpOutControl = 56588 tcpOutRsts = 803 tcpOutFastRetrans = 741 tcpInSegs =4587678 tcpInAckSegs =2087448 tcpInAckBytes =1865292802 tcpInDupAck =109461 tcpInAckUnsent = 0 tcpInInorderSegs =3877639 tcpInInorderBytes =-598404107 tcpInUnorderSegs = 14756 tcpInUnorderBytes =17985602 tcpInDupSegs = 34 tcpInDupBytes = 32759 tcpInPartDupSegs = 212 tcpInPartDupBytes =134800 tcpInPastWinSegs = 0 tcpInPastWinBytes = 0 tcpInWinProbe = 456 tcpInWinUpdate = 0 tcpInClosed = 99 tcpRttNoUpdate = 6862 tcpRttUpdate =435097 tcpTimRetrans = 15065 tcpTimRetransDrop = 67 tcpTimKeepalive = 763 tcpTimKeepaliveProbe= 1 tcpTimKeepaliveDrop = 0 IP ipForwarding = 2 ipDefaultTTL = 255 ipInReceives =11757234 ipInHdrErrors = 0 ipInAddrErrors = 0 ipInCksumErrs = 0 ipForwDatagrams = 0 ipForwProhibits = 0 ipInUnknownProtos = 0 ipInDiscards = 0 ipInDelivers =4784901 ipOutRequests =4195180 ipOutDiscards = 0 ipOutNoRoutes = 0 ipReasmTimeout = 60 ipReasmReqds = 8723 ipReasmOKs = 7565 ipReasmFails = 1158 ipReasmDuplicates = 7 ipReasmPartDups = 0 ipFragOKs = 19938 ipFragFails = 0 ipFragCreates =116953 ipRoutingDiscards = 0 tcpInErrs = 0 udpNoPorts =6426577 udpInCksumErrs = 0 udpInOverflows = 473 rawipInOverflows = 0 ICMP icmpInMsgs =490338 icmpInErrors = 0 icmpInCksumErrs = 0 icmpInUnknowns = 0 icmpInDestUnreachs = 618 icmpInTimeExcds = 314 icmpInParmProbs = 0 icmpInSrcQuenchs = 0 icmpInRedirects = 313 icmpInBadRedirects = 5 icmpInEchos = 477 icmpInEchoReps = 20 icmpInTimestamps = 0 icmpInTimestampReps = 0 icmpInAddrMasks = 0 icmpInAddrMaskReps = 0 icmpInFragNeeded = 0 icmpOutMsgs = 827 icmpOutDrops = 103 icmpOutErrors = 0 icmpOutDestUnreachs = 94 icmpOutTimeExcds = 256 icmpOutParmProbs = 0 icmpOutSrcQuenchs = 0 icmpOutRedirects = 0 icmpOutEchos = 0 icmpOutEchoReps = 477 icmpOutTimestamps = 0 icmpOutTimestampReps= 0 icmpOutAddrMasks = 0 icmpOutAddrMaskReps = 0 icmpOutFragNeeded = 0 icmpInOverflows = 0 IGMP: 0 messages received 0 messages received with too few bytes 0 messages received with bad checksum 0 membership queries received 0 membership queries received with invalid field(s) 0 membership reports received 0 membership reports received with invalid field(s) 0 membership reports received for groups to which we belong 0 membership reports sent |
以下示例显示 netstat -r 命令的输出,其中显示了 IP 路由表。
Routing Table: Destination Gateway Flags Ref Use Interface ------------------ -------------------- ----- ----- ------ --------- localhost localhost UH 0 2817 lo0 earth-bb pluto U 3 14293 eri0 224.0.0.0 pluto U 3 0 eri0 default mars-gate UG 0 14142 |
表 30–2 中介绍了 netstat -r 报告中的字段。
表 30–2 netstat -r 命令的输出
字段名 |
|
说明 |
---|---|---|
Flags |
U G H D |
路由向上。 路由通过网关。 路由到主机。 路由是使用重定向动态创建的。 |
Ref |
|
显示共享相同链路层的当前路由数。 |
Use |
|
表示发出的包的数目。 |
Interface |
|
列出用于路由的网络接口。 |