Network deployment environment under Linux

Foreword

Accordance with the requirements set ip
configures dhcp service
gateway and bridge

ip

• A description of the ip: inter proto address
  protocol name: tcp / ip
  protocol version: ipv4
  ip address: 2 ^ 32
  11111111.11111111.11111111.11111111 === 255.255.255.255
  11111110.11111110.11111110.11111110 === 254.254.254.254
  where the network equivalent position, who is equivalent to the host site. The subnet mask is used to distinguish between the two.
• Subnet Mask:
  IP Address: 11111110.11111110.11111110.11111110
  network bits: 11111111.11111111.00000000.00000000 === 255.255.0.0 (subnet mask)
  number of master range: 2 ^ 16 = 254.254.0.0 (not represented) ~ 254.254.254.254 ( broadcast address)
  real address range: 254.254.0.1 ~ 254.254.254.253 === 2 ^ 16-2
• What may communicate with two ip
  same network location, position two different hosts can directly communicate ip
  172.25.254.1/24 === 172.25.254.1/255.255.255.0
  172.25.254. * / 24 can communicate with the host

Experimental Procedure (about ip command of)

1. On the ip command (are temporary)

• Check ip address
  ip addr show
  ifconfig
• Detection network open
  ping
  -c 1 (only ping1 times)
  -w 1 (wait 1 second)
• Setting IP
  the ifconfig IP Netmask Device (format)
  the ifconfig ens33 172.25.254.11 255.255.255.0 Netmask
• Delete ip
  ip addr del 172.25.254.11/24 dev ens33
• Add ip
  ip addr the Add 172.25.254.11/24 dev ens33

Experimental Procedure (papers change ip)

1. graphically
nm-Connection-Editor
nmtui
Note: Before using these two commands, network manager must ensure that the order is on the
2. command mode
nmcli

    [root@rhel7_node1 ~]# nmcli
    agent       device      help        networking
    connection  general     monitor     radio

nmcli device status ## view device status

    [root@rhel7_node1 ~]# nmcli device status
    DEVICE      TYPE      STATE      CONNECTION
    ens33       ethernet  connected  System ens33
    virbr0      bridge    connected  virbr0
    lo          loopback  unmanaged  --
    virbr0-nic  tun       unmanaged  --

nmcli device disconnect ens33 (ip closed on the device, the device was gone)
nmcli Device Connect ens33 (open device)
nmcli Connection Show (view card information)

    [root@rhel7_node1 ~]# nmcli connection show
    NAME          UUID                                  TYPE      DEVICE
    System ens33  c96bc909-188e-ec64-3a96-6a90982b08ad  ethernet  ens33
    virbr0        d5dbe442-73b4-4e96-8748-f99d3706383b  bridge    virbr0

nmcli connection down westos (close link)
nmcli Connection up westos (open link)
nmcli the Modify Connection westos ip4 172.25.254.31/24 (add ip, added after the completion of the connection must be restarted to take effect)
nmcli Connection westos the Delete (Delete Connection)
nmcli Connection CON-name westos ifname the Add ens33 Ethernet type IP4
172.25.254.31/24 (Add connection)
connection the Add-CON Ethernet type name westos ifname ens33 ipv4.method
Auto (dhcp added network)
3 papers
arranged directories: / etc / sysconfig / network-scripts /
configuration file: ifcfg- any name
dhcp dynamic network:

vim /etc/sysconfig/network-scripts/ifcfg-westos
DEVICE=ens33(网卡名称)
ONBOOT=yes(网络服务启动网卡激活)
BOOTPROTO=dhcp(网卡工作模式为dhcp)
NAME=westos(连接名称为westos)

• Restart the network:
  : In rhel7
  systemctl restart Network ()
  in rhel8 in:
  systemctl restart NetworkManager
  nmcli Connection Down the old connection
  nmcli connection up new connections

Static Network:

vim /etc/sysconfig/network-scripts/ifcfg-westos
DEVICE=ens33(网卡名称)
ONBOOT=yes(网络服务启动网卡激活)
BOOTPROTO=none|static(网卡工作模式为dhcp)
NAME=westos(连接名称为westos)
IPADDR=172.25.254.222(IP地址)
NETMASK=255.255.255.0(子网掩码)

• Restart the network:
  rhel7 in:
  systemctl restart Network
  in rhel8 in:
  systemctl restart NetworkManager
  nmcli Connection Down the old connection
  nmcli connection up new connections

dhcp server

Experimental procedure (building dhcp server)

inrhel8In:
Configuring a static network
2. The access to the mirroring disc drive
3.df See drive mount position

    [root@localhost ~]# df
    Filesystem     1K-blocks    Used Available Use% Mounted on
    devtmpfs          910520       0    910520   0% /dev
    tmpfs             924700       0    924700   0% /dev/shm
    tmpfs             924700    9888    914812   2% /run
    tmpfs             924700       0    924700   0% /sys/fs/cgroup
    /dev/nvme0n1p3   8181760 4119960   4061800  51% /
    /dev/nvme0n1p1    199328  141328     58000  71% /boot
    tmpfs             184940      16    184924   1% /run/user/42
    tmpfs             184940    3492    181448   2% /run/user/0
    /dev/sr0         6935944 6935944         0 100% /run/media/root/RHEL-8-0-0-BaseOS-x86_64==光驱挂载点==

4. Enter the following positions

    [root@localhost root]# cd /run/media/root/RHEL-8-0-0-BaseOS-x86_64/BaseOS/Packages/
    [root@localhost Packages]# ls dhcp-*
    dhcp-client-4.3.6-30.el8.x86_64.rpm  dhcp-libs-4.3.6-30.el8.x86_64.rpm
    dhcp-common-4.3.6-30.el8.noarch.rpm  dhcp-relay-4.3.6-30.el8.x86_64.rpm
    dhcp-libs-4.3.6-30.el8.i686.rpm      dhcp-server-4.3.6-30.el8.x86_64.rpm

5. Installation DHCP (empty profile, can not start at this time)

    [root@localhost Packages]# rpm -ivh dhcp-server-4.3.6-30.el8.x86_64.rpm
    warning: dhcp-server-4.3.6-30.el8.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID fd431d51: NOKEY
    Verifying...                          ################################# [100%]
    Preparing...                          ################################# [100%]
            package dhcp-server-12:4.3.6-30.el8.x86_64 is already installed

6. dhcp configuration file
configuration directory: [root @ localhost ~] # cd / etc / dhcp /

    [root@localhost Packages]# cd /etc/dhcp/
    [root@localhost dhcp]# ls
    dhclient.conf  dhclient.d  dhcpd6.conf  dhcpd.conf(配置文件)

Generate a configuration file:

    [root@localhost dhcp]# cp /usr/share/doc/dhcp-server/dhcpd.conf.example /etc/dhcp/dhcpd.conf

Add line numbers and show: vim /etc/dhcp/dhcpd.conf

    1 # dhcpd.conf
    2 #
    3 # Sample configuration file for ISC dhcpd
    4 #
    5
    6 # option definitions common to all supported networks...
    7 option domain-name "westos.com";  （域名设定）
    8 option domain-name-servers 114.114.114.114;   #dns
    9
    10 default-lease-time 600;
    11 max-lease-time 7200;
    12
    13 # Use this to enble / disable dynamic dns updates globally.
    14 #ddns-update-style none;
    15
    16 # If this DHCP server is the official DHCP server for the local
    17 # network, the authoritative directive should be uncommented.
    18 #authoritative;
    19
    20 # Use this to send dhcp log messages to a different log file
    (you also
    21 # have to hack syslog.conf to complete the redirection).
    22 log-facility local7;
    23
    24 # No service will be given on this subnet, but declaring it
    helps the
    25 # DHCP server to understand the network topology.
    26
    27 subnet 10.152.187.0 netmask 255.255.255.0 {   #删除
    28 }   #删除
    29
    30 # This is a very basic subnet declaration.
    31
    32 subnet 172.25.254.0 netmask 255.255.255.0 {  #设定网段
    33 range 172.25.254.100 172.25.254.200;    #分配地址范围
    34 option routers 172.25.254.10;   #网关
    35 }
    36 ################以下内容全部删除###################
    37 # This declaration allows BOOTP clients to get dynamic
    addresses,
    38 # which we don't really recommend.
    .........

7. Restart Service systemctl restart dhcpd detection state and

    [root@localhost dhcp]# systemctl restart dhcpd
    [root@localhost dhcp]# systemctl status dhcpd
    ● dhcpd.service - DHCPv4 Server Daemon
       Loaded: loaded (/usr/lib/systemd/system/dhcpd.service; disabled; vendor pres>
       Active: active (running) since Tue 2020-03-17 22:26:41 CST; 1min 18s ago
         Docs: man:dhcpd(8)
               man:dhcpd.conf(5)
     Main PID: 33180 (dhcpd)
       Status: "Dispatching packets..."
        Tasks: 1 (limit: 11380)
       Memory: 7.7M
       CGroup: /system.slice/dhcpd.service
               └─33180 /usr/sbin/dhcpd -f -cf /etc/dhcp/dhcpd.conf -user dhcpd -gro>
    ......

8. Test
rhel7 in the dhcp ip network to see if you can get
to see the card in rhel7 physical hardware address

    [root@rhel7_node1 network-scripts]# ifconfig
    ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
    inet 172.25.254.100 netmask 255.255.255.0 broadcast
    172.25.254.255
    inet6 fe80::20c:29ff:fe4e:5b61 prefixlen 64 scopeid
    0x20<link>
    ether 00:0c:29:4e:5b:61 txqueuelen 1000 (Ethernet)   (**物理硬件地址**)
    RX packets 22740 bytes 7150801 (6.8 MiB)
    RX errors 0 dropped 0 overruns 0 frame 0
    TX packets 6810 bytes 744115 (726.6 KiB)
    TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

Check in ip allocation in rhel8

    root@localhost ~]# cat /var/lib/dhcpd/dhcpd.leases
    #The format of this file is documented in the dhcpd.leases(5) manual
    page.
    ##This lease file was written by isc-dhcp-4.3.6
    #authoring-byte-order entry is generated, DO NOT DELETE
    authoring-byte-order little-endian;
    server-duid "\000\001\000\001%\332\216M\000\014)\217\340\321";
    lease 172.25.254.100 {     (分配出去的ip)
    starts 6 2020/02/15 11:14:04;
    ends 6 2020/02/15 11:24:04;
    cltt 6 2020/02/15 11:14:04;
    binding state active;
    next binding state free;
    rewind binding state free;
    hardware ethernet 00:0c:29:4e:5b:61;  (获取此ip的网卡硬件地址)
    client-hostname "rhel7_node1";
    }

* Note: In the following rhel7 mounted in dhcp

    cd "/run/media/root/RHEL-7.6 Server.x86_64/Packages"
    rpm -ivh dhcp-4.2.5-68.el7_5.1.x86_64.rpm

Gateway

Suppose a host A 192.168.0.11
there is a host B 172.25.254.11
because two hosts not in the same network segment, even if the network cable is connected, two hosts can not communicate with each other, if desired, between each two hosts communications, you need a router.
This router 172 and the side segment, while segment 192 and communication.
Kernel routing enables direct communication ip different network segments.
The main function of a router isNAT(Network Address Translation)

• Get this card ip gateway:
  router and gateway client host in the same network segment ip called the client host

• Gateway setting mode
  command mode: <temporary>
  Via the Add default route ip 172.25.254.100 # Add a default gateway
  via ip route del default 172.25.254.100 # delete the default gateway
  papers: <Permanent>
  way to modify the system global gateway 1

  vim /etc/sysconfig/network
  GATEWAY=172.25.254.10
  

  inrhel8In
  systemctl restart NetworkManager
  nmcli Connection Down link name
  nmcli connection up link name
  inrhel7中
  systemctl stop NetworkManager
  systemctl restart network
  systemctl start NetworkManager

  2. Modify the gateway mode network card set (only works on the card against)

     vim /etc/sysconfig/network-scripts/ifcfg-westos
     DEVICE=ens160
     ONBOOT=yes
     BOOTPROTO=none
     IPADDR=172.25.254.10
     NETMASK=255.255.255.0
     GATEWAY=172.25.254.100    #网关   
  

  inrhel8In
  systemctl restart NetworkManager
  nmcli Connection Down link name
  nmcli connection up link name
  inrhel7中
  systemctl stop NetworkManager
  systemctl restart network

Experimental procedure (the router communicates different network)

The premise of the case:
there are two windows on virtual systems, are rhel7 and rhel8
windows: 192.168.0.103
rhel8: 172.25.254.10
rhel7 ready to act as a router, it is set to be confirmed

1. Add an NIC rhel7 into the dual card host so that the host rhel7

    在虚拟机上添加一块网卡，选择桥接模式
    编辑 vim  /etc/sysconfig/network-scripts/ifcfg-ens38文件
    DEVICE=ens38
    ONBOOT=yes
    BOOTPROTO=none
    IPADDR=172.25.254.100
    NETMASK=255.255.255.0
    NAME=westos

2. Set rhel7 host address for two network cards:
the card 1ens33: 192.168.0.100 (and windows hosts in a unified network segments)
card 2ens38: 172.25.254.100 (rhel8 host in a unified network segment)

    [root@rhel7_node1 network-scripts]# ifconfig
    ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 192.168.0.100  netmask 255.255.255.0  broadcast 192.168.0.255
            inet6 fe80::20c:29ff:fe1d:b92  prefixlen 64  scopeid 0x20<link>
            ether 00:0c:29:1d:0b:92  txqueuelen 1000  (Ethernet)
            RX packets 90864  bytes 31948435 (30.4 MiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 22379  bytes 2869247 (2.7 MiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

    ens38: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 172.25.254.100  netmask 255.255.255.0  broadcast 172.25.254.255
            inet6 fe80::20c:29ff:fe1d:b9c  prefixlen 64  scopeid 0x20<link>
            ether 00:0c:29:1d:0b:9c  txqueuelen 1000  (Ethernet)
            RX packets 1701  bytes 143745 (140.3 KiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 71  bytes 7989 (7.8 KiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

3. Open the kernel routing function in rhel7

    [root@rhel8_node1 network-scripts]# sysctl -a |grep ip_forward
    .....
    net.ipv4.ip_forward = 0     #表示内核路由功能未开启
    .....

Open core routing function:

    vim /etc/sysctl.conf
         net.ipv4.ip_forward=1      #开启内核路由功能
    sysctl -p                 #设定更改立即生效

4. Open the rhel7 address masquerading function (by the firewall to Controls)

    [root@rhel7_node1 network-scripts]# systemctl start firewalld
    [root@rhel7_node1 network-scripts]# firewall-cmd --list-all
            public (active)
            target: default
            icmp-block-inversion: no
            interfaces: ens33 ens38
            sources:
            services: ssh dhcpv6-client
            ports:
            protocols:
            masquerade: no  #地址伪装功能未开启
            forward-ports:
            source-ports:
            icmp-blocks:
            rich rules:
    [root@rhel7_node1 network-scripts]# firewall-cmd --permanent --add-masquerade
    [root@rhel7_node1 network-scripts]# firewall-cmd --reload

After the operation is complete:

    [root@rhel7_node1 network-scripts]# firewall-cmd --list-all
    public (active)
      target: default
      icmp-block-inversion: no
      interfaces: ens33 ens38
      sources:
      services: ssh dhcpv6-client
      ports:
      protocols:
      masquerade: yes  #地址伪装开启
      forward-ports:
      source-ports:
      icmp-blocks:
      rich rules:

test
In rhel8:
1. Can Test communication:

    ping 192.168.0.103  #测试能否和windows主机通信，测试结果为不能

2. Add Gateway:

    ip route add default via 172.25.254.100  #添加本机网关为172.25.254.100

3.route -n # query Gateway

    [root@localhost ~]# route -n
    Kernel IP routing table
    Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
    0.0.0.0         172.25.254.100  0.0.0.0         UG    0      0        0 ens160
    172.25.254.0    0.0.0.0         255.255.255.0   U     100    0        0 ens160
    172.25.254.100  0.0.0.0         255.255.255.255 UH    0      0        0 ens160

4. Again Detection:

    [root@localhost ~]# ping 192.168.0.103
    PING 192.168.0.103 (192.168.0.103) 56(84) bytes of data.
    64 bytes from 192.168.0.103: icmp_seq=1 ttl=63 time=1.69 ms
    64 bytes from 192.168.0.103: icmp_seq=2 ttl=63 time=0.553 ms
    64 bytes from 192.168.0.103: icmp_seq=3 ttl=63 time=1.52 ms

DNS

dns: responsible for domain names into ip of this work is called the host dns server (ARP)

• dns server pointing to a temporary file:

    vim /etc/resolv.conf  ##
    nameserver 114.114.114.114  ##114.114.114.114 为电信dns服务
  

  Equivalent:
  the ping www.baidu.com -----> /etc/resolv.conf ----> 114.114.114.114 ----> www.baidu.com = 39.156.66.18

• Local parse the file (provisional):

    vim /etc/hosts     #叫做本地解析文件(很有限，需要手动加入)
    39.156.66.18     www.baidu.com
  

• dns permanent settings:

   vim /etc/sysconfig/network-scripts/ifcfg-ens160  #
   DNS1=114.114.114.114
   DNS2=
   DNS3=
  

Network Service Restart

Experimental Procedure (understand DNS)

1. Setting the host ip and windows in a network
2. Set the same host gateway windows
3. See www.baidu.com Baidu ping ip in windows
4. In linux ping ip can Baidu
5. ping in linux www.baidu.com not
6. writing / etc / hosts
39.156.66.18 www.baidu.com
the ping www.baidu.com can
www.qq.com not the ping
7. change /etc/resolv.conf
nameserver 114.114.114.114
can ping www.qq.com

Bridge

Network bridge is a bridge that helps virtual machines and network connection directly, without going through the host kernel.

Experimental Procedure (bridge setting)

1. Delete the original card link:

nmcli connection delete System\ ens160

2. Modify the network card configuration file:

vim /etc/sysconfig/network-scripts/ifcfg-ens160
DEVICE=ens160
ONBOOT=yes
BOOTPROTO=none
BRIDGE=br0

3. Modify the bridge interface configuration file:

vim /etc/sysconfig/network-scripts/ifcfg-br0
DEVICE=br0
ONBOOT=yes
BOOTPROTO=none
IPADDR=172.25.254.10
NETMASK=255.255.255.0
TYPE=Bridge

4. Restart network services:

systemctl restart NetworkManager

5. Test:

[root@localhost ~]# bridge link show
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master br0 state forwarding priority 32 cost 100 
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 master virbr0 state disabled priority 32 cost 100 

At this time, the virtual machines and physical machines in parallel on network environment, the virtual machine does not take up core communications network with a physical machine Oh.

postscript

nat way and what the nature of each bridge