"Network basic series Two" BOOTP, DHCP protocol

BOOTP

meaning : Boot Protocol, boot protocol

function : Boot the diskless computer or the computer that was started for the first time to obtain the following network configuration information:

• The host's IP address, subnet mask
• IP address of the router (gateway)
• DNS Server IP Address

C/S protocol:

• CLIENT:UDP 68 Port
• SERVER:UDP 67 Port

Static Configuration Protocol:

meaning : The binding of the BOOTP client's physical address to the IP address is preset on the BOOTP server.

　　 Note : The meaning of "static" does not refer to the static of the acquisition method, but refers to the configuration of the client's physical address and IP address when the binding relationship is initialized, and is not changed in the BOOTP server at a later stage.

BOOTP operation

1, BOOTP use UDP,BOOTP server has been in a passive response state, waiting to accept customer requests;

2, the client sends the UDP request from 68 port, the server has been in the listening state, when the supervisor hears the request passes over the request to receive from 67 port;

3, the server responds to the request: the server still sends the corresponding message from the 67 port to the customer, the customer also receives the response message from the Send Port 68.

The red border is a BOOTP package, the outer gray is a UDP package, the SP is the source address, and DA is the destination address.

, the BOOTP encapsulated SP is the port number 68, the destination address is the port number 67, and the UDP package source address is all 0, because the main purpose of using the BOOTP protocol is to obtain the local IP address and other information, the key is that the customer does not know the local address, so use all 0, the destination address using all 1, Indicates that the client is not clear where the BOOTP server is, and therefore chooses the broadcast mode for forwarding, all 1 represents the broadcast address.

, the BOOTP encapsulated SP is the port number 67, the destination address is the port number 68, and the request message corresponds to the source address and the destination address is the opposite, while the UDP package source address is the server is the IP address, the destination address can use the target customer's address and can use all 1 broadcast, The so-called all roads lead to Rome, the result is the same.

Dhcp

Meaning: Dynamic Host configuration Protocol, dynamically configured protocol, RFC 2131

Role:

1. BOOTP extensions and enhancements, backward compatibility with BOOTP
2. Provides temporary static or dynamic configuration for a limited period of time

• Static database: The binding of a manually configured physical address and IP address, stored in a static database
• IP address pool: The remaining available IP addresses to be allocated are stored in the IP address pool

Network basic Series two BOOTP, DHCP protocol