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网络管理基础

  Network interface names

  Traditionally, network interfaces in Linux are enumerated as eth0, eth1, eth2, and so on. However, the mechanism which

  sets these names can cause changes to which interface gets which name as devices are added and removed.

  The default naming behavior in Red Hat Enterprise Linux 7 is to assign fixed names based on firmware, device topology,

  and device type.

  Interface names have the following characters:

  Ethernet interfaces begin with en, WLAN interfaces begin with wl, and WWAN interfaces begin with ww.

  The next character(s) represents the type of adapter with an o for on-board, s for hotplug slot, and p for PCI geographic location.

  Not used by default but also available to administrators, an x is used to incorporate a MAC address.

  Finally, a number N is used to represent an index, ID, or port.

  If the fixed name cannot be determined, the traditional names such as ethN will be used.

  For example, the first embedded network interface may be named eno1 and a PCI card network interface may be named enp2s0.

  The new names make it easier to distinguish the relationship between a port and its name if the user knows both, but the

  trade off is that users cannot assume a system with one interface calls that interface eth0.

  使用NetworkManager管理网络

  网络管理器(NetworkManager)是一个动态网络的控制器与配置系统,它用于当网络设备可用时保持设备和连接开启并激活

  默认情况下,CentOS/RHEL 7 已安装网络管理器,并处于启用状态。

  device 设备,物理设备 例如enp2s0,virbr0,team0

  connection 连接,逻辑设置 指的是一套具体配置方案

  多个connection可以应用到同一个device,但同一时间只能启用其中一个connection。

  这样的好处是针对一个网络接口,可以设置多个网络连接,比如静态IP和动态IP,再根据需要up相应的connection

  NetworkManager提供的工具

  nmcli, nmtui, nm-connect-editor

  1. 方法一: 修改ip/netmask/dns/gateway[了解]

  [root@tianyun ~]# nmcli connection add con-name enp2s0-auto autoconnect yes ifname enp2s0 type ethernet

  [root@tianyun ~]# nmcli connection add con-name enp2s0-gun autoconnect yes ifname enp2s0 type ethernet ip4 10.10.10.10/24 gw4 10.10.10.254

  [root@tianyun ~]# nmcli connection show enp2s0-auto |grep ipv4.me

  ipv4.method: auto

  [root@tianyun ~]# nmcli connection show enp2s0-gun |grep ipv4.me

  ipv4.method: manual

  [root@tianyun ~]# ls /etc/sysconfig/network-scripts/

  ifcfg-enp2s0 ifdown-ippp ifdown-TeamPort ifup-ipv6 ifup-Team

  ifcfg-enp2s0-auto ifdown-ipv6 ifdown-tunnel ifup-isdn ifup-TeamPort

  ifcfg-enp2s0-gun ifdown-isdn ifup ifup-plip ifup-tunnel

  [root@tianyun ~]# nmcli connection up enp2s0-auto

  [root@tianyun ~]# nmcli connection delete enp2s0-auto

  [root@tianyun ~]# nmcli connection modify enp2s0-gun ipv4.method a

  [root@tianyun ~]# nmcli connection modify enp2s0-gun ipv4.method m

  [root@tianyun ~]# nmcli connection modify enp2s0-gun +ipv4.addresses 20.20.20.20/24

  [root@tianyun ~]# nmcli connection modify enp2s0-gun +ipv4.dns 114.114.114.114

  [root@tianyun ~]# nmcli connection show enp2s0-gun |grep ipv4.add

  ipv4.addresses: 10.10.10.10/24, 20.20.20.20/24

  2. 方法二:修改ip/netmask/dns/gateway

  [root@tianyun ~]# vim /etc/sysconfig/network-scripts/ifcfg-enp2s0

  NAME="enp2s0"

  DEVICE="enp2s0"

  ONBOOT=yes

  NETBOOT=yes

  BOOTPROTO=none

  IPADDR=172.16.120.246

  PREFIX=24

  IPADDR1=192.168.200.246

  PREFIX1=24

  GATEWAY=172.16.120.254

  DNS1=8.8.8.8

  DNS2=114.114.114.114

  [root@tianyun ~]# nmcli con reload

  [root@tianyun ~]# nmcli con down enp2s0; nmcli con up enp2s0

  注:删除自建的连接connection

  不使用NetworkManager管理网络

  aliyun

  [root@aliyun ~]# nmcli connection delete enp2s0-auto

  [root@aliyun ~]# systemctl disable NetworkManager

  [root@aliyun ~]# systemctl stop NetworkManager

  [root@aliyun ~]# systemctl status NetworkManager

  ● NetworkManager.service - Network Manager

  Loaded: loaded (/usr/lib/systemd/system/NetworkManager.service; disabled; vendor preset: enabled)

  Active: inactive (dead)

  [root@aliyun ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0

  NAME=eth0

  DEVICE=eth0

  ONBOOT=yes

  NETBOOT=yes

  BOOTPROTO=none

  IPADDR=192.168.122.169

  PREFIX=24

  TYPE=Ethernet

  [root@aliyun ~]# systemctl restart network.service

  以下配置跟NetworkManager无关:

  1. 修改主机名/etc/hostname

  # hostnamectl set-hostname tianyun.example.com

  # cat /etc/hostname

  # reboot

  2. 配置名字解析Configuring name resolution

  a. hosts

  [root@tianyun ~]# cat /etc/hosts

  127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4

  ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6

  119.75.218.70 www.baidu.com

  [root@tianyun ~]# getent hosts www.baidu.com

  119.75.218.70 www.baidu.com

  b. resolv.conf DNS

  [root@tianyun ~]# cat /etc/resolv.conf

  # Generated by NetworkManager

  nameserver 114.114.114.114

  [root@tianyun ~]# yum -y install bind-utils

  [root@tianyun ~]# host www.sina.com

  www.sina.com is an alias for us.sina.com.cn.

  us.sina.com.cn is an alias for wwwus.sina.com.

  wwwus.sina.com has address 66.102.251.33

  基本的网络测试工具

  [root@tianyun ~]# ip a

  [root@tianyun ~]# ip a s eth0

  [root@tianyun ~]# ip route

  [root@tianyun ~]# ip neigh

  [root@tianyun ~]# hostname

  [root@tianyun ~]# ping www.baidu.com

  [root@tianyun ~]# ping -c2 www.baidu.com

  [root@tianyun ~]# ip -s link show eth0

  [root@tianyun ~]# traceroute www.sina.com

  [root@tianyun ~]# tracepath www.sina.com

  1?: [LOCALHOST] pmtu 1500

  1: no reply

  2: 11.245.87.126 0.787ms

  3: 106.11.130.218 0.387ms

  4: 42.120.244.125 0.425ms

  5: 150.138.132.157 1.469ms

  6: 150.138.128.241 3.546ms asymm 7

  7: 202.97.40.241 24.677ms

  8: 202.97.24.154 14.197ms

  9: 202.97.33.154 18.340ms asymm 10

  10: 202.97.90.242 182.632ms

  11: 203.14.186.138 193.383ms asymm 13

  12: 218.30.41.234 209.543ms asymm 13

  13: 66.102.251.33 163.224ms reached

  Resume: pmtu 1500 hops 13 back 14

  查看设备物理连接的状态

  [root@tianyun ~]# ip a

  2: enp1s0: mtu 1500 qdisc pfifo_fast master br0 state DOWN qlen 1000

  如果在连接禁用 ONBOOT=no 以上的信息不真实

  [root@tianyun ~]# ethtool enp1s0

  Link detected: no

  ports and services

  以下为示例服务:

  [root@aliyun ~]# yum -y install httpd vsftpd

  [root@aliyun ~]# systemctl start httpd

  [root@aliyun ~]# systemctl start vsftpd

  http 80/tcp

  https 443/tcp

  ssh 22/tcp

  ftp 21/tcp

  1. Show TCP sockets (LISTEN)

  [root@aliyun ~]# ss -tnl

  State Recv-Q Send-Q Local Address:Port Peer Address:Port

  LISTEN 0 128 *:80 *:*

  LISTEN 0 128 *:8080 *:*

  LISTEN 0 10 114.215.71.214:53 *:*

  LISTEN 0 10 10.29.89.165:53 *:*

  LISTEN 0 10 127.0.0.1:53 *:*

  LISTEN 0 128 *:22 *:*

  LISTEN 0 128 127.0.0.1:953 *:*

  LISTEN 0 128 127.0.0.1:6010 *:*

  LISTEN 0 128 *:443 *:*

  LISTEN 0 32 :::21 :::*

  LISTEN 0 10 :::53 :::*

  [root@aliyun ~]# ss -tnl |grep :80

  LISTEN 0 128 *:80 *:*

  [root@aliyun ~]# ss -tnl |grep :21

  LISTEN 0 32 :::21 :::*

  [root@aliyun ~]# ss -atn

  State Recv-Q Send-Q Local Address:Port Peer Address:Port

  LISTEN 0 128 *:80 *:*

  LISTEN 0 10 114.215.71.214:53 *:*

  LISTEN 0 10 10.29.89.165:53 *:*

  LISTEN 0 10 127.0.0.1:53 *:*

  LISTEN 0 128 *:22 *:*

  LISTEN 0 128 127.0.0.1:953 *:*

  LISTEN 0 128 127.0.0.1:6010 *:*

  ESTAB 0 52 114.215.71.214:22 123.120.38.233:49603

  ESTAB 0 0 114.215.71.214:40962 140.205.140.205:80

  LISTEN 0 32 :::21 :::*

  LISTEN 0 10 :::53 :::*

  [root@aliyun ~]# ss -atn |grep :22

  LISTEN 0 128 *:22 *:*

  ESTAB 0 52 114.215.71.214:22 123.120.38.233:49603

  [root@aliyun ~]# ss -atn |grep :80

  LISTEN 0 128 *:80 *:*

  ESTAB 0 0 114.215.71.214:40962 140.205.140.205:80

  a 所有状态,包括 LISTEN

  2. Show UDP sockets (所有状态)

  [alice@tianyun ~]$ ss -anu

  State Recv-Q Send-Q Local Address:Port Peer Address:Port

  UNCONN 0 0 114.215.71.214:53 *:*

  UNCONN 0 0 10.29.89.165:53 *:*

  UNCONN 0 0 127.0.0.1:53 *:*

  UNCONN 0 0 114.215.71.214:123 *:*

  UNCONN 0 0 10.29.89.165:123 *:*

  UNCONN 0 0 127.0.0.1:123 *:*

  UNCONN 0 0 *:123 *:*

  UNCONN 0 0 :::53 :::*

  UNCONN 0 0 :::123 :::*

  [kiosk@foundation0 ~]$ ss -tan |grep :5910

  LISTEN 0 5 *:5910 *:*

  ESTAB 0 0 172.25.254.250:5910 172.25.254.44:51435

  ESTAB 0 0 172.25.254.250:5910 172.25.254.6:40546

  ESTAB 0 0 172.25.254.250:5910 172.25.254.18:37780

  ESTAB 0 0 172.25.254.250:5910 172.25.254.13:55841

  ESTAB 0 0 172.25.254.250:5910 172.25.254.35:36984

  ESTAB 0 0 172.25.254.250:5910 172.25.254.9:47342

  ESTAB 0 0 172.25.254.250:5910 172.25.254.2:40955

  ESTAB 0 0 172.25.254.250:5910 172.25.254.12:50833

  ESTAB 0 0 172.25.254.250:5910 172.25.254.36:50854

  ESTAB 0 0 172.25.254.250:5910 172.25.254.1:52444

  ESTAB 0 0 172.25.254.250:5910 172.25.254.47:39335

  ESTAB 10 0 172.25.254.250:5910 172.25.254.14:55833

  临时配置网络信息

  ip/netmask

  # ip addr add dev eth1 3.3.3.3/24

  # ip addr del dev eth1 3.3.3.3/24

  gateway

  # ip route del default

  # ip route add default via 192.168.122.3

  # ip route add 10.10.10.0/24 via 192.168.122.5

  hostname

  # hostname tianyun.cc.com

  配置文件:

  #vim /etc/sysconfig/network-scripts/ifcfg-eth0

  DEVICE=eth0 设备名称

  【NAME="System eth0" 设备名称】 可以不存在

  BOOTPROTO=none 启动协议 获取ip地址的方式 static、none ==>静态获取 dhcp 动态

  NM_CONTROLLED=no 默认是yes 关闭network-manager

  ONBOOT=yes 开机启动

  TYPE=Ethernet 以太网类型

  HWADDR=00:0c:29:8e:a5:d3 mac地址

  IPADDR=172.16.80.252 ip地址

  NETMASK=255.255.0.0 掩码

  PREFIX =24

  NETWORK=172.16.0.0

  GATEWAY=172.16.80.1 网关

  dns domain name server 域名解析

  帮助文档:

  #vim /usr/share/doc/initscripts-9.03.38/sysconfig.txt

  网关:网络的关卡(出口),一般设置到路由器上

  IP转发:

  临时

  # echo 1 > /proc/sys/net/ipv4/ip_forward

  永久

  # vim /etc/sysctl.conf 修改内核参数

  net.ipv4.ip_forward = 1

  # sysctl -p //立即生效

  dns : 域名服务器,其中一种是解析域名到Ip地址

  dns配置文件(客户端)

  #vim /etc/resolv.conf

  nameserver 172.16.70.250

  查看mac

  #arping 172.16.70.250

  扫描ip

  #nmap -v -sP 172.16.70.0/24

  扫描端口

  #nmap -v -A 172.16.70.0/24

  重启网络服务:

  #systemctl restart network //rhel7

  #/etc/init.d/network restart //rhel5/6

  #service network restart //rhel5/6

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