Principles of Linux Network Foundation Network
Network addressing IP Addressing IP addressing is a two-tier addressing scheme, an IP address identifies a host (or a NIC interface)
Now the most widely used Ipv4 addressing, has begun to gradually switch to Ipv6 addressing
Ipv4 address is 32 bits long, Ipv6 address is 128 bits long
One
The Ipv4 address is divided into two parts: the network part and the host part
The network section is used to identify which host in the zone and the host part is used to identify the
IP Address
The Ipv4 address is divided into 32-bit lengths and is typically expressed in dotted-decimal terms
The entire IP address is divided into 4 parts, 8 bits per section
For example:
192.168.1.1
11000000.10101000.00000001.00000001
Subnet mask Ipv4 address 32 bits are divided into network parts and host parts
Because the number of bits in the network and host parts of different IP addresses is not fixed, how do you determine which parts of the IP address are part of the network?
To determine the number of bits in a network section by using a subnet mask
The subnet mask, like the IP address, has 32 bits, each corresponding to each bit of the IP address one by one.
IP address and subnet mask must be a pair of objects in order to determine the network portion of the IP, alone can not be judged.
The portion of the IP address that corresponds to 1 in the subnet mask is the network part.
For example:
IP Address 192.168.1.1
11000000.10101000.00000001.00000001
It corresponds to the subnet mask
255.255.255.0
11111111.11111111.11111111.00000000
Prove that the first 24 bits of this IP address are the network portion, that is, the first 24 bits of the IP address of the other hosts on the same network as this IP address, to prove that they are on the same network.
Determine whether you are on the same network by comparing whether the network part is the same.
The network part of the IP address is similar to the home address, and the host part resembles the personal name
Communication between the same network and communication between the same network also needs to use a addressing that is the MAC address, the MAC address is used in the same network between the host communication, the same network within the host is directly connected through the switch.
The MAC address is the Cure address on the NIC and the hardware address of the NIC.
Hosts in the same network need to communicate with the underlying MAC address to understand the physical path, this is the hardware addressing.
First, send an ARP message, ARP (Address Resolution Protocol)
The source host normally does not know the destination host's MAC address, only the IP address, the destination host's MAC address is required.
The communication between different networks accesses different networks, because the IP address of the destination network is not known, so an additional router or gateway is required, which must be forwarded through the router.
The function of routing data between different networks is called routing, which usually has multiple interfaces, connects to different networks, and transmits data through the routing table.
Routing table:
Target Network subnet mask out interface
192.168.1.0 255.255.255.0 eth0
172.16.1.0 255.255.0.0 eth1
61.1.1.0 255.255.255.252 eth2
The computer will send the address to the router as long as it discovers the destination network address and is not on the same network segment.
The router checks to see if the routing table has a record of reaching the target network, and if so, sends the data from the appropriate interface.
Domain name IP addresses are often difficult to remember, so we use domain names for management.
Www.linux.net
The domain name is divided into three sections, using a. Split
Type identifies the type of this domain name
Domain Name City
Hostname The name of a host in the domain name
WWW: hostname linux: Domain name net: type
DNS each domain name represents an IP, and the DNS service is used to convert between IP and domain names.
Www.linux.net 61.1.1.1
The DNS service is provided by the DNS server
Visit: www.linux.net
1:dns Access Requests
DNS Server
2:www.linux.net=61.1.1.1
3: Visit www.linux.net
Configuring Network information requires:
IP address, subnet mask, gateway, DNS
Basic network parameters to configure a computer for LAN communication:
IP Address
Subnet mask
To configure a computer to communicate across a network segment:
IP Address
Subnet mask
Gateway
To configure an Internet-accessible computer:
IP Address
Subnet mask
Gateway
Dns
Basics of getting Started with Linux-network fundamentals
