我遇到了一个奇怪的问题， ping返回的响应时间几乎固定在98ms 。
要么我ping通网关，要么ping本地主机或互联网主机。 虽然实际的延迟是显而易见的，但响应时间总是在98ms左右。
但是，反向ping（从本地计算机到此主机）正常工作。
以下是我的路线表和结果：
route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.1.1 0.0.0.0 UG 100 0 0 eth1 60.194.136.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth1 192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 # ping the gateway ping 192.168.1.1 PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data. 64 bytes from 192.168.1.1: icmp_req=1 ttl=64 time=98.7 ms 64 bytes from 192.168.1.1: icmp_req=2 ttl=64 time=97.0 ms 64 bytes from 192.168.1.1: icmp_req=3 ttl=64 time=96.0 ms 64 bytes from 192.168.1.1: icmp_req=4 ttl=64 time=94.9 ms 64 bytes from 192.168.1.1: icmp_req=5 ttl=64 time=94.0 ms ^C --- 192.168.1.1 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4004ms rtt min/avg/max/mdev = 94.030/96.149/98.744/1.673 ms #ping a local machine ping 192.168.1.88 PING 192.168.1.88 (192.168.1.88) 56(84) bytes of data. 64 bytes from 192.168.1.88: icmp_req=1 ttl=64 time=98.7 ms 64 bytes from 192.168.1.88: icmp_req=2 ttl=64 time=96.9 ms 64 bytes from 192.168.1.88: icmp_req=3 ttl=64 time=96.0 ms 64 bytes from 192.168.1.88: icmp_req=4 ttl=64 time=95.0 ms ^C --- 192.168.1.88 ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 3003ms rtt min/avg/max/mdev = 95.003/96.696/98.786/1.428 ms #ping a internet host ping google.com PING google.com (74.125.128.139) 56(84) bytes of data. 64 bytes from hg-in-f139.1e100.net (74.125.128.139): icmp_req=1 ttl=42 time=99.8 ms 64 bytes from hg-in-f139.1e100.net (74.125.128.139): icmp_req=2 ttl=42 time=99.9 ms 64 bytes from hg-in-f139.1e100.net (74.125.128.139): icmp_req=3 ttl=42 time=99.9 ms 64 bytes from hg-in-f139.1e100.net (74.125.128.139): icmp_req=4 ttl=42 time=99.9 ms ^C64 bytes from hg-in-f139.1e100.net (74.125.128.139): icmp_req=5 ttl=42 time=99.9 ms --- google.com ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 32799ms rtt min/avg/max/mdev = 99.862/99.925/99.944/0.284 ms
我正在运行iperf来testing带宽，对于局域网连接，速率非常低。
iperf -c 192.168.1.87 -t 50 -i 10 -f M ------------------------------------------------------------ Client connecting to 192.168.1.87, TCP port 5001 TCP window size: 0.06 MByte (default) ------------------------------------------------------------ [ 4] local 192.168.1.139 port 54697 connected with 192.168.1.87 port 5001 [ ID] Interval Transfer Bandwidth [ 4] 0.0-10.0 sec 6.12 MBytes 0.61 MBytes/sec [ 4] 10.0-20.0 sec 6.38 MBytes 0.64 MBytes/sec [ 4] 20.0-30.0 sec 6.38 MBytes 0.64 MBytes/sec [ 4] 30.0-40.0 sec 6.25 MBytes 0.62 MBytes/sec [ 4] 40.0-50.0 sec 6.38 MBytes 0.64 MBytes/sec [ 4] 0.0-50.1 sec 31.6 MBytes 0.63 MBytes/sec
ping会尝试对IP地址进行DNS PTR查询，这可能是您看到的延迟。 运行ping -n禁用。
您也可能会看到针对非ICMPstream量的不同行为。 尝试使用hping在各个端口上发送UDP和TCP数据包来检查这一点。
iperf udp模式更能代表实际的帧转换时延和故障率。
一些面向会话的tcptesting掩盖了损失。
还有一些很酷的东西可以用iperf做，比如抖动测量。