nmap显示在针对除localhost之外的ip运行时打开的端口较少

Question

我在vmware工作站有一个虚拟机,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

我在盒子本身上运行命令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类似阻塞端口的东西,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运行时显示更少的端口.

Answer 1

为什么nmap在针对localhost运行时显示更多端口打开,而在针对ip运行时显示更少端口

有些应用程序决定bind只在localhost上显式监听(实际上),即127.0.0.1.你可以做一个netstat检查.