Network configuration file
IP, MASK, GW, DNS-related configuration files:/etc/sysconfig/network-scripts/ifcfg-iface
Device: Devices to which this profile applies, determine the device name
HWADDR: MAC address of the corresponding device
Bootproto: The address configuration protocol used when activating this device, commonly used DHCP----dynamic, static---static, none---manually specified, BOOTP
nm_controlled: NM is a shorthand for NetworkManager, does this NIC accept NM control; CentOS6 recommended "No"
onboot: Whether this device is activated at system boot time; recommended Yes
Type: interface types; common Ethernet, Bridge.
UUID: Unique identification of the device
ipaddr: Specify IP Address
NETMASK: Subnet mask equivalent to prefix= digit
Gateway: Default gateways
DNS1: The first DNS server points to a
DNS2: The second DNS server points to a
Userctl: Whether a normal user can control this device
Peerdns: If the value of Bootproto is "DHCP", whether to allow DHCP server to assign a DNS server to direct the information to overwrite the /etc/resolv.conf file
Routing-related configuration files:/etc/sysconfig/network-scripts/route-iface
Note: Requires service network restart to take effect
Two different styles:
(1) TARGET via GW
such as: 10.0.0.0/8 via 172.16.0.1
(2) Define one route per three lines
Address#=target
Netmask#=mask
Gateway#=gw
DNS name Resolution
DNS configuration file; /etc/resolv.conf
Search Localdomain #你的域名
NameServer 192.168.61.1 #DNS
[[email protected] ~]# Ping www
PING www.ghosts2.com (101.200.188.230) bytes of data.
Your domain name is www.ghosts2.com.
Nic Aliases
Useful for the same physical NIC for a virtual host
Ifconfig command:
Ifconfig eth0:0 192.168.1.100/24 up
Ifconfig eth0:0 Down
IP command:
IP addr Add 172.16.1.2/16 dev eth0 label eth0:0
IP addr del 172.16.1.1/16 dev eth0 label eth0:0
IP addr Flush Dev eth0 label eth0:0 Remove NIC Aliases
Alias in effect: Copy network profile CP Ifcfg-eth0 Ifcfg-eth0:1 then vim ifcfg-eth0:1 edit configuration DEVICE name corresponds to eth0:1 NIC alias need to manually configure IP, not automatically generated
Implementing A to B communication in a single-sided route
Route C IP is 192.168.61.140/24 nic eth1
| Routing 192.168.61.0/24
Switch
| |
A host------------------------| |----------------------B Host
A IP is 172.18.253.37/16 eth1 B IP is 192.168.61.150/24 eth1
A Route 172.18.0.0/16 B Route 192.168.0.0/24
Do the following for C
Increase the NIC alias for route C
[[Email protected] ~] #cp ifcfg-eth1 ifcfg-eth1:0
Edit Network Card settings
[[Email protected] ~]#vim ifcfg-eth1:0
name=eth1:0
device=eth1:0
ipaddr=172.18.253.40
Prefix=16
Increase routing configuration
[[Email protected] ~] #ip route add 172.18.0.0/16 Dev eth1:0
Turn on route forwarding for C
[[Email protected] ~] #echo 1>/proc/sys/net/ipv4/ip_forward
Network Interface Configuration-bonding
Bonding is to bind multiple network cards to the same IP address to provide services externally, can achieve high availability or load balancing. Of course, it is not possible to set the same IP address directly for two NICs. Through bonding, a virtual one network card to provide external connection, the physical network card is modified to the same MAC address
Mode 0 (BALANCE-RR)
Rotation (round-robin) strategy: Send packets above and below each slave interface in a sequential order. This mode provides load balancing and fault tolerance capabilities
Mode 1 (active-backup)
Active-Backup (Master) policy: Only one slave is activated, and the other slave is activated only if the active slave interface fails. To prevent the switch from confusing, the bound MAC address is visible on only one external port
Mode 3 (broadcast)
Broadcast strategy: Transmit all messages on all slave interfaces, providing fault tolerance
Bonding configuration:
Create a configuration file for a bonding device
/etc/sysconfig/network-scripts/ifcfg-bond0
Device=bond0
Bootproto=none manually specifying IP
bonding_opts= "miimon=100 mode=0" specified mode
/etc/sysconfig/network-scripts/ifcfg-eth0
Device=eth0
Bootproto=none
Master=bond0
Slave=yes
Userctl=no
View bond0 status :/proc/net/bonding/bond0
Delete Bond0
(1) ifconfig bond0 down
(2) Rmmod bonding
(3) Modify Ifcfg-eth0 ifcfg-eth1 configuration file to remove Master SLAVE
Implementing eth1 eth0 Binding the same IP address
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Modify Host Name
1. Modify the command to take effect
Hostnamectl--static Set-hostname kami777
2. Edit/etc/hosts Add host Name
127.0.0.1 kami777 localhost localhost.localdomain localhost4 localhost4.localdomain4
Kami777 corresponding IP is 127.0.0.1
The host file acts quite like DNS, providing the IP address to the corresponding hostname
The Linux system issues a domain name resolution request to the DNS server to query the/etc/host file and, if there is a corresponding record, use the records in the hosts
Modify the /etc/sysconfig/network in CETOS6
Getent hosts view/etc/hosts content
change centos7 nic name eno16777736 to Eth0
1. Modify the NIC configuration file name
[Email protected] ~]# cd/etc/sysconfig/network-scripts/
[Email protected] ~]# MV ifcfg-eno16777736 Ifcfg-eth0
2. Modify the configuration file name device two items
[Email protected] ~]# vim Ifcfg-eth0
Name=eth0
Device=eth0
3. Modify/etc/sysconfig/grub Add net.ifname=0
grub_cmdline_linux= "Crashkernel=auto net.ifnames=0 rhgb quiet"
4. Regenerate GRUB Configuration Update kernel parameters
[[email protected] ~] #grub2-mkconfig-o/boot/grub2/grub.cfg successfully restarted
Client 1 to Client 2 routing configuration (no routing in the middle of the same network segment)
Known Client 1:
IP is
inet 172.18.251.197 netmask 255.255.0.0 broadcast 172.18.255.255
Routing is configured to
Destination Gateway genmask Flags Metric Ref use Iface
172.18.0.0 0.0.0.0 255.255.0.0 U 0 0 eth0
Client 2:
IP for process
inet addr:192.168.61.139 bcast:192.168.61.255 mask:255.255.255.0
Routing is configured to
Destination Gateway genmask Flags Metric Ref use Iface
192.168.61.0 0.0.0.0 255.255.255.0 U 1 0 0 Eth3
[[Email protected] ~] #ping 172.18.251.197
Connect:network is unreachable
No client 2-to-client 1 routes are pointing, Ping is not through, and the routing table is increased in Client 2
[[email protected] ~] #route Add default GW 192.168.61.1 dev eth3 defaults gateway specify next hop to find IP not in routing table
Destination Gateway genmask Flags Metric Ref use Iface
192.168.61.0 0.0.0.0 255.255.255.0 U 1 0 0 Eth3
0.0.0.0 192.168.61.1 0.0.0.0 U 0 0 0 Eth3
[[Email protected] ~] #ping 172.18.251.197
PING 172.18.251.197 (172.18.251.197) bytes of data.
From 192.168.61.139 icmp_seq=7 Destination Host Unreachable
End 1 No end 2 routing location has to go back, need to increase the routing location at the end 1
[[Email protected] ~] #route Add default GW 172.18.0.1 dev eth0
Destination Gateway genmask Flags Metric Ref use Iface
172.18.0.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0
0.0.0.0 172.18.0.1 0.0.0.0 U 0 0 0 eth0
End 1 receives and responds and joins the record to the routing table
192.168.61.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0
Linux Network-related configuration