nmap显示在针对除localhost之外的ip运行时打开的端口较少

时间:2012-08-10 16:37:13

标签: linux port nmap

我在vmware工作站中有一个虚拟机,它是桥接网络和DHCP。 DHCP服务器分配的IP为10.21.245.22。这是我的/ etc / hosts看起来像:

127.0.0.1 hadoop-namenode-01 localhost

我在盒子上运行命令A和B.

命令A:

root @ hadoop-namenode-01:〜#nmap -sT -sU -p- localhost

Starting Nmap 5.21 ( http://nmap.org ) at 2012-08-10 09:32 PDT
Nmap scan report for localhost (127.0.0.1)
Host is up (0.00029s latency).
rDNS record for 127.0.0.1: hadoop-namenode-01
Not shown: 131058 closed ports
PORT      STATE         SERVICE
22/tcp    open          ssh
53/tcp    open          domain
631/tcp   open          ipp
8020/tcp  open          unknown
9000/tcp  open          cslistener
9001/tcp  open          tor-orport
50070/tcp open          unknown
53/udp    open|filtered domain
68/udp    open|filtered dhcpc
123/udp   open          ntp
5353/udp  open|filtered zeroconf
47982/udp open|filtered unknown

Nmap done: 1 IP address (1 host up) scanned in 12.45 seconds

命令B:

root @ hadoop-namenode-01:〜#nmap -sT -sU -p- 10.21.245.22

Starting Nmap 5.21 ( http://nmap.org ) at 2012-08-10 09:28 PDT
Nmap scan report for wn7x64-3jql0q1.dub.emea.dell.com (10.21.245.22)
Host is up (0.00029s latency).
Not shown: 131065 closed ports
PORT      STATE         SERVICE
22/tcp    open          ssh
68/udp    open|filtered dhcpc
123/udp   open          ntp
5353/udp  open|filtered zeroconf
47982/udp open|filtered unknown

Nmap done: 1 IP address (1 host up) scanned in 12.20 seconds

我的问题是:

因为我没有防火墙或阻塞端口之类的东西,为什么nmap在针对localhost运行时显示更多端口打开,而当它针对ip运行时显示的端口更少。

2 个答案:

答案 0 :(得分:7)

  

为什么nmap在针对localhost运行时显示更多端口打开   当它与ip运行时显示较少的端口

某些应用程序决定仅在localhost上显式监听(bind实际上),即127.0.0.1。您可以执行netstat检查。

答案 1 :(得分:1)

Linux中的大多数系统运行过程都使用环回(127.0.0.1)ip地址进行相互通信。它不需要在网络外发送数据包。