ping 返回的TTL数值代表什么？
1 [[email protected] ~]# dig @202.106.0.20 www.iqiyi.com 2 3 ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.30.rc1.el6 <<>> @202.106.0.20 www.iqiyi.com 4 ; (1 server found) 5 ;; global options: +cmd 6 ;; Got answer: 7 ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 22053 8 ;; flags: qr rd ra; QUERY: 1, ANSWER: 7, AUTHORITY: 0, ADDITIONAL: 0 9 10 ;; QUESTION SECTION: 11 ;www.iqiyi.com. IN A 12 13 ;; ANSWER SECTION: 14 www.iqiyi.com. 7 IN CNAME static.dns.iqiyi.com. 15 static.dns.iqiyi.com. 6 IN A 111.206.13.65 16 static.dns.iqiyi.com. 6 IN A 111.206.13.63 17 static.dns.iqiyi.com. 6 IN A 111.206.13.61 18 static.dns.iqiyi.com. 6 IN A 111.206.13.64 19 static.dns.iqiyi.com. 6 IN A 111.206.13.62 20 static.dns.iqiyi.com. 6 IN A 111.206.13.66 21 22 ;; Query time: 6 msec 23 ;; SERVER: 202.106.0.20#53(202.106.0.20) 24 ;; WHEN: Thu Sep 15 17:25:09 2016 25 ;; MSG SIZE rcvd: 152
查看一共经历几跳路由
1 [[email protected] ~]# traceroute www.iqiyi.com 2 traceroute to www.iqiyi.com (111.206.13.63), 30 hops max, 60 byte packets 3 1 localhost (192.168.1.1) 2.924 ms 2.662 ms 2.429 ms 4 2 * * * 5 3 61.148.174.189 (61.148.174.189) 3.744 ms 3.555 ms 7.079 ms 6 4 124.65.58.237 (124.65.58.237) 6.910 ms 6.263 ms 6.062 ms 7 5 61.51.115.106 (61.51.115.106) 5.852 ms 5.635 ms 5.420 ms 8 6 bt-211-046.bta.net.cn (202.106.211.46) 6.722 ms 8.319 ms 8.019 ms 9 7 111.206.13.63 (111.206.13.63) 7.183 ms 3.643 ms 6.609 ms 10 [[email protected] ~]#
查看返回的TTL
1 [[email protected] ~]# ping www.iqiyi.com 2 PING static.dns.iqiyi.com (111.206.13.63) 56(84) bytes of data. 3 64 bytes from 111.206.13.63: icmp_seq=1 ttl=58 time=7.56 ms 4 64 bytes from 111.206.13.63: icmp_seq=2 ttl=58 time=9.46 ms 5 ^C 6 --- static.dns.iqiyi.com ping statistics --- 7 2 packets transmitted, 2 received, 0% packet loss, time 1957ms 8 rtt min/avg/max/mdev = 7.569/8.516/9.464/0.951 ms 9 [[email protected] ~]#
64 - 6 = 58
已知经过6跳路由，那么我们尝试设置ttl为6进行试验：
1 [[email protected] ~]# ping -c 3 -t 6 www.iqiyi.com 2 PING static.dns.iqiyi.com (111.206.13.66) 56(84) bytes of data. 3 From bt-211-046.bta.net.cn (202.106.211.46) icmp_seq=1 Time to live exceeded 4 From bt-211-046.bta.net.cn (202.106.211.46) icmp_seq=2 Time to live exceeded 5 From bt-211-046.bta.net.cn (202.106.211.46) icmp_seq=3 Time to live exceeded 6 7 --- static.dns.iqiyi.com ping statistics --- 8 3 packets transmitted, 0 received, +3 errors, 100% packet loss, time 2017ms
已知经过6跳路由，那么我们尝试设置ttl为7进行试验：
1 [[email protected] ~]# ping -c 3 -t 7 www.iqiyi.com 2 PING static.dns.iqiyi.com (111.206.13.65) 56(84) bytes of data. 3 64 bytes from 111.206.13.65: icmp_seq=1 ttl=58 time=6.25 ms 4 64 bytes from 111.206.13.65: icmp_seq=2 ttl=58 time=12.1 ms 5 64 bytes from 111.206.13.65: icmp_seq=3 ttl=58 time=5.23 ms 6 7 --- static.dns.iqiyi.com ping statistics --- 8 3 packets transmitted, 3 received, 0% packet loss, time 2008ms 9 rtt min/avg/max/mdev = 5.233/7.885/12.167/3.057 ms 10 [[email protected] ~]#
时间： 2024-10-10 00:57:20