我在外部和内部的服务器表单上扫描，为什么结果不同？
[root@xxx ~]# nmap -sV -p 0-65535 localhost Starting Nmap 5.51 ( http://nmap.org ) at 2011-02-16 07:59 MSK Nmap scan report for localhost (127.0.0.1) Host is up (0.000015s latency). rDNS record for 127.0.0.1: localhost.localdomain Not shown: 65534 closed ports PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 4.3 (protocol 2.0) 80/tcp open http Apache httpd 2.2.3 ((CentOS)) Service detection performed. Please report any incorrect results at http://nmap.org/submit/ . Nmap done: 1 IP address (1 host up) scanned in 7.99 seconds 和
sh-3.2# nmap -sV -p 0-65535 xxx.com Starting Nmap 5.51 ( http://nmap.org ) at 2011-02-16 00:01 EST Warning: Unable to open interface vmnet1 -- skipping it. Warning: Unable to open interface vmnet8 -- skipping it. Stats: 0:07:49 elapsed; 0 hosts completed (1 up), 1 undergoing SYN Stealth Scan SYN Stealth Scan Timing: About 36.92% done; ETC: 00:22 (0:13:21 remaining) Stats: 0:22:05 elapsed; 0 hosts completed (1 up), 1 undergoing Service Scan Service scan Timing: About 75.00% done; ETC: 00:23 (0:00:02 remaining) Nmap scan report for xxx.com (xxxx) Host is up (0.22s latency). Not shown: 65528 closed ports PORT STATE SERVICE VERSION 21/tcp open tcpwrapped 22/tcp open ssh OpenSSH 4.3 (protocol 2.0) 25/tcp open tcpwrapped 80/tcp open http Apache httpd 2.2.3 ((CentOS)) 110/tcp open tcpwrapped 143/tcp open tcpwrapped 443/tcp open tcpwrapped 8080/tcp open http-proxy?
ssh和http有一个INADDR_ANY侦听器，所以你可以在loopback和extern iface（netstat -naltp会显示你在ssh监听0.0.0.0:22和http监听0.0.0.0:80）上看到这两个。
tcpwrapped和http-proxy只在外部iface上侦听。
两件事情：
这可能是由于您的防火墙configuration。 当你扫描本地主机时，它会绕过适用于真实接口（如eth0）的防火墙规则，并find所有正在侦听的服务。
将networking服务设置为仅侦听特定接口通常是很好的安全措施。 因此，例如端口8080上的http-proxy可以configuration为忽略localhost上的请求。