nmap，缺少最后一个 mac 地址

Question

当我运行

sudo nmap -sn xxx.xxx.x.*

我得到了连接到我的路由器的所有 IP 的列表（xxx.xxx.x.1 是网关），但我注意到最后连接的 ip 没有显示 MAC 地址。为什么？我怎样才能解决这个问题？这是我的输出：

Starting Nmap 7.60 ( https://nmap.org ) at 2018-04-09 18:38 CEST
Nmap scan report for xxx.xxx.x.1
Host is up (0.0029s latency).
MAC Address: xx:xx:xx:xx:xx:xx (Technicolor)
Nmap scan report for xxx.xxx.x.2
Host is up (0.00014s latency).
MAC Address: xx:xx:xx:xx:xx:xx (Prime Electronics & Satellitics)
Nmap scan report for xxx.xxx.x.3
Host is up (0.16s latency).
MAC Address: xx:xx:xx:xx:xx:xx (Espressif)
Nmap scan report for xxx.xxx.x.46
Host is up (1.1s latency).
MAC Address: xx:xx:xx:xx:xx:xx (Xiaomi Communications)
Nmap scan report for xxx.xxx.x.61
Host is up (1.4s latency).
MAC Address: xx:xx:xx:xx:xx:xx (Unknown)
Nmap scan report for xxx.xxx.x.128
Host is up (8.3s latency).
MAC Address: xx:xx:xx:xx:xx:xx (Motorola Mobility, a Lenovo Company)
Nmap scan report for xxx.xxx.x.254
Host is up.
MAC Address: xx:xx:xx:xx:xx:xx (Unknown)
Nmap scan report for xxx.xxx.x.27
Host is up.
Nmap done: 256 IP addresses (8 hosts up) scanned in 27.83 seconds

如您所见，MAC 最后一个主机（即我的电脑，我从中执行命令）缺少地址

Answer 1

最后一个IP是你的扫描机。因为它是通过环回接口访问的，所以它没有关联的 MAC 地址。 Loopback link 类型没有物理介质，因此它不需要或没有 "media access control" (MAC) 地址。它被列在最后是因为 Nmap 首先扫描了一组中所有使用以太网（或类似物，如 WiFi）的目标link，最后一组只留下你的本地地址。

nmap，缺少最后一个 mac 地址

nmap, missing last mac address

ip

networking

nmap