【题目】网络面试题

1. 查看当前系统每IP连接数

[root@oldboy ~]# netstat -an
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address               Foreign Address             State      
tcp        0      0 0.0.0.0:3306                0.0.0.0:*                   LISTEN      
tcp        0      0 0.0.0.0:22                  0.0.0.0:*                   LISTEN      
tcp        0      0 192.168.0.109:22            192.168.0.102:49801         ESTABLISHED 
tcp        0      0 :::22                       :::*                        LISTEN      
udp        0      0 0.0.0.0:68                  0.0.0.0:*                               
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags       Type       State         I-Node Path
unix  5      [ ]         DGRAM                    9255   /dev/log
unix  2      [ ACC ]     STREAM     LISTENING     9766   /var/lib/mysql/mysql.sock
unix  2      [ ACC ]     STREAM     LISTENING     7096   @/com/ubuntu/upstart
unix  2      [ ]         DGRAM                    7497   @/org/kernel/udev/udevd
unix  2      [ ]         DGRAM                    13757  
unix  2      [ ]         DGRAM                    11955  
unix  2      [ ]         DGRAM                    9802   
unix  3      [ ]         DGRAM                    7515   
unix  3      [ ]         DGRAM                    7514 

# 过滤其中状态为ESTABLISHED的记录
[root@oldboy ~]# netstat -an|grep "ESTABLISHED"   
tcp        0      0 192.168.0.109:22            192.168.0.102:49801         ESTABLISHED 

# 过滤ip
[root@oldboy ~]# netstat -an|grep "ESTABLISHED"|awk '{print $4}'
192.168.0.109:22
[root@oldboy ~]# netstat -an|grep "ESTABLISHED"|awk '{print $4}'|awk -F: '{print $1}'  
192.168.0.109

# 多个ip则排序后再计数
[root@oldboy ~]# netstat -an|grep "ESTABLISHED"|awk '{print $4}'|awk -F: '{print $1}'|sort -n
192.168.0.109
[root@oldboy ~]# netstat -an|grep "ESTABLISHED"|awk '{print $4}'|awk -F: '{print $1}'|sort -n|uniq -c
      1 192.168.0.109

2. 请列出以下服务使用的端口

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转载自www.cnblogs.com/zoe233/p/11914194.html