我想远程检查一些服务器是否启动。
我不使用ping命令，因为由于networking基础设施不良，导致许多错误的结果，例如“目标主机不可达”和“请求超时”。
我尝试使用nmap命令通过打开的端口来检查服务器。 Nmap为我提供了真正的开放端口，但是当我closures服务器和接入点时，nmap仍然报告它正在运行。
我通过USB调制解调器连接到互联网，我检查的目标主机通过带有USB调制解调器和静态IP的TP-Link接入点连接到互联网。
当我完全closures远程访问点时，我在本地机器上运行这个命令：
nmap -p 80 -vv 105.198.224.47 Starting Nmap 7.01 ( https://nmap.org ) at 2017-01-31 11:54 EET Initiating Ping Scan at 11:54 Scanning 105.198.224.47 [2 ports] Completed Ping Scan at 11:54, 0.61s elapsed (1 total hosts) Initiating Parallel DNS resolution of 1 host. at 11:54 Completed Parallel DNS resolution of 1 host. at 11:54, 0.01s elapsed Initiating Connect Scan at 11:54 Scanning 105.198.224.47 [1 port] Discovered open port 80/tcp on 105.198.224.47 Completed Connect Scan at 11:54, 0.09s elapsed (1 total ports) Nmap scan report for 105.198.224.47 Host is up, received syn-ack (0.55s latency). Scanned at 2017-01-31 11:54:17 EET for 0s PORT STATE SERVICE REASON 80/tcp open http syn-ack Read data files from: /usr/bin/../share/nmap Nmap done: 1 IP address (1 host up) scanned in 0.78 seconds 当把ip放在浏览器中时，它给出：
"This site can't be reached" "The connection was reset."
这种情况发生在打开和closures的两种情况下，但是我没有在主机上设置任何http服务器。
接入点打开时跟踪路由给出：
traceroute to 105.198.224.47 (105.198.224.47), 30 hops max, 60 byte packets 1 192.168.9.1 (192.168.9.1) 1.667 ms 1.768 ms 2.508 ms 2 * * * 3 10.255.224.106 (10.255.224.106) 759.425 ms 769.911 ms 770.401 ms 4 10.255.224.114 (10.255.224.114) 770.142 ms 770.508 ms 770.871 ms 5 10.255.224.124 (10.255.224.124) 771.866 ms 771.859 ms 779.227 ms 6 105.199.1.3 (105.199.1.3) 780.458 ms 792.637 ms 792.453 ms 7 163.121.143.88 (163.121.143.88) 803.571 ms 51.573 ms 41.250 ms 8 163.121.143.75 (163.121.143.75) 49.261 ms 49.264 ms 49.384 ms 9 * * * 10 * * * 11 * * * 12 * * * 13 * * * 14 * * * 15 * * * 16 * * * 17 * * * 18 * * * 19 * * * 20 * * * 21 * * * 22 * * * 23 * * * 24 * * * 25 * * * 26 * * * 27 * * * 28 * * * 29 * * * 30 * * *
在接入点closures时运行跟踪路由给出相同的结果，但仅在毫秒毫秒的值中进行更改。
那么，这个行为的解释是什么呢？