linux 101-200

103 Linux 重要子目录说明

/etc/sysconfig/net-scripts/ifcfg-eth0

1)重启网卡 /etc/init.d/network restart

2)ifdown eth0 && ifup eth0 只针对eth0网卡，通过setup network configuration 修改

DEVICE=eth0          物理设备名  eth1表示第二块网卡
HWADDR=00:0c:29:a6:a6:6d   网卡mac地址   48位
TYPE=Ethernet   以太网
UUID=a1d78f1f-e337-4366-8600-8b53579f9f95  网卡的唯一标识   身份证一样
ONBOOT=yes        是不是开机启动
NM_CONTROLLED=yes
BOOTPROTO=dhcp      none，引导时不使用协议    static 静态分配地址   bootp，使用bootp 协议，   dhcp 使用dhcp协议
USERCTL=no
PEERDNS=yes
IPV6INIT=no

查看磁盘设备的UUID 可以使用blkid 查看

[root@lodboy ~]# blkid
/dev/sda3: UUID="bfd0887f-fbd2-474e-a4df-20d051eec917" TYPE="ext4" 
/dev/sda1: UUID="244e62b6-2f8a-486a-a620-daa11b3fe4f0" TYPE="ext4" 
/dev/sda2: UUID="61aa510b-94fb-4c1e-ac14-4a45e6ee6933" TYPE="swap"

查看网关

[root@lodboy ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.92.0    0.0.0.0         255.255.255.0   U     0      0        0 eth0
169.254.0.0     0.0.0.0         255.255.0.0     U     1002   0        0 eth0
0.0.0.0         192.168.92.2    0.0.0.0         UG    0      0        0 eth0

查看DNS

[root@lodboy ~]# cat /etc/resolv.conf 
; generated by /sbin/dhclient-script
search localdomain
nameserver 192.168.92.2

[root@lodboy ~]# cat /etc/resolv.conf
; generated by /sbin/dhclient-script
search localdomain
nameserver 192.168.92.2
nameserver 114.114.114.114

小结：

1、linux 客户端DNS可以在网卡配置文件里设置 ifcfg-eth0

2,linux客户端DNS也可以在/etc/resolv.cong里设置

3，网卡里的设置DNS优先于/etc/resolv.conf，如果重启网络网卡的DNS会覆盖/etc/resolv.conf

重启网卡

1，全部重启

[root@lodboy ~]# /etc/init.d/network restart
Shutting down interface eth0:                              [  OK  ]
Shutting down loopback interface:                          [  OK  ]
Bringing up loopback interface:                            [  OK  ]
Bringing up interface eth0:  
Determining IP information for eth0... done.
                                                           [  OK  ]

2，重启单块网卡

[root@lodboy ~]# ifdown eth0 && ifup  eth0

Determining IP information for eth0... done.

查看链接状态

[root@lodboy ~]# netstat -an | grep 192
tcp        0     52 192.168.92.227:22           192.168.92.1:53434          ESTABLISHED 
[root@lodboy ~]#

查看IP地址

[root@lodboy ~]# ip add
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:a6:a6:6d brd ff:ff:ff:ff:ff:ff
    inet 192.168.92.227/24 brd 192.168.92.255 scope global eth0
    inet6 fe80::20c:29ff:fea6:a66d/64 scope link 
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
    link/ether 00:0c:29:a6:a6:77 brd ff:ff:ff:ff:ff:ff
[root@lodboy ~]# 
[root@lodboy ~]# 
[root@lodboy ~]# ip add | grep 192
    inet 192.168.92.227/24 brd 192.168.92.255 scope global eth0

105 Linux 重要子目录说明

/etc/hosts