Partitioning and configuring routing of IP Addresses

IP address: is a way of addressing the host on the Internet, also known as an Internetwork protocol address. Common IP address, divided into IPv4 and IPv6 two major categories;

Routing: Routers can connect network devices that are not the same network segment, enabling them to establish communication;

IP Address Classification

Class A: (the first eight bits are the network address: fixed)

0 000 0000-0 111 1111:1-127

Number of networks: 126, 127

Number of hosts per network: 2^24-2

Default Subnet Mask: 255.0.0.0

Public network address: 1.0.0.0-9.255.255.255; 11.0.0.0-126.255.255.255

Private network Address: 10.0.0.0-10.255.255.255

Class B: (the first 16 bits are the network address: fixed)

10 00 0000-10 11 1111:128-191

Network number: 2^14

Number of hosts per network: 2^16-2

Default Subnet Mask: 255.255.0.0

Public network address: 128.0.0.0-172.15.255.255; 172.32.0.0-191.255.255.255

Private network Address: 172.16.0.0-172.31.255.255

Class C: ()

110 0 0000-110 1 1111:192-223

Network number: 2^21

Number of hosts per network: 2^8-2

Default Subnet Mask: 255.255.255.0

Public network address: 192.0.0.0-192.167.255.255; 192.169.0.0-233.255.255.255

Private network Address: 192.168.0.0-192.168.255.255

Class D: Multicast

1110 0000-1110 1111:224-239

Class E:

240-255

Special Address:

0.0.0.0:

0.0.0.0 is not an IP address in the real sense. It represents a collection: All the unclear hosts and destination networks;

255.255.255.255:

Restrict broadcast addresses. For this machine, this address refers to all hosts within the network segment (the same broadcast domain);

127.0.0.1 ~127.255.255.254

A native loopback address that is used primarily for testing. Packets with the destination address "127.0.0.1" should never appear on the transmission medium;

224.0.0.0 to 239.255.255.255

multicast address, 224.0.0.1 refers specifically to all hosts, 224.0.0.2 specifically all routers; 224.0.0.5 means OSPF routers, and addresses are used for a number of specific programs and multimedia programs;

169.254.x.x

If the Windows host uses DHCP to automatically assign an IP address and cannot obtain an address from the DHCP server, the system assigns such an address to the host;

CIDR (Non-class inter-domain routing):

CIDR is defined by a subnet mask;

The subnet mask defines the number of bits of the network ID and the number of bits of the host ID;

The subnet mask is also a 32 bit binary number;

The subnet mask is used to represent the number of bits of the network ID, with 0 indicating the number of bits of the host ID;

Subnet Mask (mask)

Common calculation formula for IP address:

Equation 1:

Number of hosts in a network segment =2^ host bits-2

Number of host ID bits =32-network ID bits

Equation 2:

Network ID=IP and subnet masks

Equation 3:

Dividing subnets:

A large net is divided into several small nets

Network ID to host ID borrow N, subnet number 2^n

(Dividing subnet is only divided the borrowed bit)

Equation 4:

Loss ip= (number of subnets 2^n-1)

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Classification and management of routing

Routing: cross-network communication;

Routing classifications:

Host routing

Network routing

Default route

Routing Management Commands:

The route command is a network command that displays and modifies entries in the local IP routing table;

View: Route-n

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Add: Route add

Route add [-net|-host] target [netmask Nm] [GW GW] [[Dev] If]

Target: 192.168.1.3 Gateway: 172.16.0.1

# route add-host 192.168.1.3 GW 172.16.0.1 Dev eth0

Target: 192.168.0.0 Gateway: 172.16.0.1

# route add-net 192.168.0.0 netmask 255.255.255.0 gw 172.16.0.1 Dev eth0

# route add-net 192.168.0.0/24 GW 172.16.0.1 Dev eth0

Default route, Gateway: 172.16.0.1

# route add-net 0.0.0.0 netmask 0.0.0.0 GW 172.16.0.1

# route add default GW 172.16.0.1

Delete: Route del

Route del [-net|-host] target [GW GW] [netmask Nm] [[Dev] If]

Target: 192.168.1.3 Gateway: 172.16.0.1

# route Del-host 192.168.1.3

Target: 192.168.0.0 Gateway: 172.16.0.1

# route del-net 192.168.0.0 netmask 255.255.255.0

To configure a routing instance:

1, two hosts configured with two network cards to act as two routes R1 and R2;

Routing R1

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Routing R2

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2, configure IP addresses and gateways for two hosts PC1 and PC2 respectively:

PC1

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PC2

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3,centos 6 shutting down the NetworkManager service and shutting down the firewall:

Shut down the NetworkManager services: Service NetworkManager stop

Firewall off: iptables-f

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4,centos shutting down the NetworkManager service and shutting down the firewall:

Close NetworkManager service: Systemctl stop NetworkManager

Firewall off: iptables-f

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5, add the default gateway to the routing table in route R1:

Route add default GW 10.1.0.8

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6, add the default gateway to the routing table in route R2:

Route add default GW 10.1.0.6

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7. Turn on data conversion for routing R1:

Echo 1 >/proc/sys/net/ipv4/ip_forward

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8. Turn on data conversion for routing R2:

Echo 1 >/proc/sys/net/ipv4/ip_forward

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9, with PC1 gradually to spell PC2:

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10, with PC2 gradually to spell PC1:

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Partitioning and configuring routing of IP Addresses