1. 命令: ifconfig
ifconfig用来配置常驻内核的网络接口信息。在系统启动必要时用来设置网络适配器的信息。之后，它通常是只需要在调试时或当系统需要调整时使用。
检查活动网络适配器
[avishek@tecmint ~]$ ifconfig
eth0 Link encap:Ethernet HWaddr 40:2C:F4:EA:CF:0E
inet addr:192.168.1.3 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::422c:f4ff:feea:cf0e/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:163843 errors:0 dropped:0 overruns:0 frame:0
TX packets:124990 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:154389832 (147.2 MiB) TX bytes:65085817 (62.0 MiB)
Interrupt:20 Memory:f7100000-f7120000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:78 errors:0 dropped:0 overruns:0 frame:0
TX packets:78 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:4186 (4.0 KiB) TX bytes:4186 (4.0 KiB)
检查所有的网络适配器
“-a”参数用来显示所有网络适配器(网卡)的详细信息,包括那些停用的适配器。
[avishek@tecmint ~]$ ifconfig -a
eth0 Link encap:Ethernet HWaddr 40:2C:F4:EA:CF:0E
inet addr:192.168.1.3 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::422c:f4ff:feea:cf0e/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:163843 errors:0 dropped:0 overruns:0 frame:0
TX packets:124990 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:154389832 (147.2 MiB) TX bytes:65085817 (62.0 MiB)
Interrupt:20 Memory:f7100000-f7120000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:78 errors:0 dropped:0 overruns:0 frame:0
TX packets:78 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:4186 (4.0 KiB) TX bytes:4186 (4.0 KiB)
virbr0 Link encap:Ethernet HWaddr 0e:30:a3:3a:bf:03
inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
停用网络适配器
[avishek@tecmint ~]$ ifconfig eth0 down
启用网络适配器
[avishek@tecmint ~]$ ifconfig eth0 up
指定IP地址到网络适配器
为网络适配器eth0设定IP地址“192.168.1.12”.
[avishek@tecmint ~]$ ifconfig eth0 192.168.1.12
更改网络适配器eth0的子网掩码
[avishek@tecmint ~]$ ifconfig eth0 netmask 255.255.255.
更改网络适配器eth0的广播地址
[avishek@tecmint ~]$ ifconfig eth0 broadcast 192.168.1.255
为网络适配器eth0指定IP地址,子网掩码，广播地址
[avishek@tecmint ~]$ ifconfig eth0 192.168.1.12 netmask 255.255.255.0 broadcast 192.168.1.255
注Note:如果你设置一块无线网卡的信息,你可以使用的命令是“iwconfig”.欲知更多ifconfig命令的例子和使用方法，读“15个有用的ifconfig 命令”.
2. 命令: netstat
netstat命令显示各种网络相关的信息，如网络连接,路由表,接口统计,伪装连接,组播成员身份等….
列出所有的网络端口
[avishek@tecmint ~]$ netstat -a
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 741379 /run/user/user1/keyring-I5cn1c/gpg
unix 2 [ ACC ] STREAM LISTENING 8965 /var/run/acpid.socket
unix 2 [ ACC ] STREAM LISTENING 18584 /tmp/.X11-unix/X0
unix 2 [ ACC ] STREAM LISTENING 741385 /run/user/user1/keyring-I5cn1c/ssh
unix 2 [ ACC ] STREAM LISTENING 741387 /run/user/user1/keyring-I5cn1c/pkcs11
unix 2 [ ACC ] STREAM LISTENING 20242 @/tmp/dbus-ghtTjuPN46
....
显示所有tcp相关端口
[avishek@tecmint ~]$ netstat -at
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 localhost:mysql *:* LISTEN
tcp 0 0 *:5901 *:* LISTEN
tcp 0 0 *:5902 *:* LISTEN
tcp 0 0 *:x11-1 *:* LISTEN
tcp 0 0 *:x11-2 *:* LISTEN
tcp 0 0 *:5938 *:* LISTEN
tcp 0 0 localhost:5940 *:* LISTEN
...
显示所有连接的统计信息
[avishek@tecmint ~]$ netstat -s
Ip:
994239 total packets received
0 forwarded
0 incoming packets discarded
165741 incoming packets delivered
3248924 requests sent out
8 outgoing packets dropped
Icmp:
29460 ICMP messages received
166 input ICMP message failed.
ICMP input histogram:
destination unreachable: 98
redirects: 29362
2918 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
destination unreachable: 2918
IcmpMsg:
InType3: 98
InType5: 29362
OutType3: 2918
Tcp:
94533 active connections openings
23 passive connection openings
1870 failed connection attempts
7194 connection resets received
....
好的!由于某些原因如果你不想解析netstat 输出的主机、端口和用户名称的话 。
[avishek@tecmint ~]$ netstat -an
好，你可能需要获取的 netstat 持续输出的动态信息，通过传递中断输出指令 (ctrl + c)来停止。
[avishek@tecmint ~]$ netstat -c
更多关于“netstat”的例子和使用方法，浏览文章“20个netstat 的使用案例”。
3. 命令： nslookup
网络实用程序，用于获得互联网服务器的信息。顾名思义，该实用程序将发现通过查询 DNS 域的名称服务器信息。
[avishek@tecmint ~]$ nslookup tecmint.com
Server: 192.168.1.1
Address: 192.168.1.1
#53
Non-authoritative answer:
Name: tecmint.com
Address: 50.16.67.239
查询邮件交换器记录
[avishek@tecmint ~]$ nslookup -query=mx tecmint.com
Server: 192.168.1.1
Address: 192.168.1.1
#53
Non-authoritative answer:
tecmint.com mail exchanger = 0 smtp.secureserver.net.
tecmint.com mail exchanger = 10 mailstore1.secureserver.net.
Authoritative answers can be found from:
查询域名服务器
[avishek@tecmint ~]$ nslookup -type=ns tecmint.com
Server: 192.168.1.1
Address: 192.168.1.1
#53
Non-authoritative answer:
tecmint.com nameserver = ns3404.com.
tecmint.com nameserver = ns3403.com.
Authoritative answers can be found from:
查询DNS记录
[avishek@tecmint ~]$ nslookup -type=any tecmint.com
Server: 192.168.1.1
Address: 192.168.1.1
#53
Non-authoritative answer:
tecmint.com mail exchanger = 10 mailstore1.secureserver.net.
tecmint.com mail exchanger = 0 smtp.secureserver.net.
tecmint.com nameserver = ns06.domaincontrol.com.
tecmint.com nameserver = ns3404.com.
tecmint.com nameserver = ns3403.com.
tecmint.com nameserver = ns05.domaincontrol.com.
Authoritative answers can be found from:
查询起始授权机构
[avishek@tecmint ~]$ nslookup -type=soa tecmint.com
Server: 192.168.1.1
Address: 192.168.1.1
#53
Non-authoritative answer:
tecmint.com
origin = ns3403.hostgator.com
mail addr = dnsadmin.gator1702.hostgator.com
serial = 2012081102
refresh = 86400
retry = 7200
expire = 3600000
minimum = 86400
Authoritative answers can be found from:
查询端口号
更改使用你想要连接的端口号
[avishek@tecmint ~]$ nslookup -port 56 tecmint.com
Server: tecmint.com
Address: 50.16.76.239
#53
Name: 56
Address: 14.13.253.12
4. 命令: dig
dig是查询DNS 域名服务器的工具，可以查询的主机地址、 邮件交流、 域名服务器相关的信息。在任何 Linux (Unix) 或 Macintosh OS X 操作系统上，都可以使用该工具。dig的最典型的用法是单个主机的查询。
[avishek@tecmint ~]$ dig tecmint.com
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6 <<>> tecmint.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<
关闭注释行
[avishek@tecmint ~]$ dig tecmint.com +nocomments
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6 <<>> tecmint.com +nocomments