table of Contents
- Description of DNS domain name system and how it works.
- Description of the HTTP protocol and how it works.
- HTTP packet format?
- The method of the HTTP request message what?
- Http1.1 and http2.0 the difference?
- http return code as well as representatives of the meaning?
- Brief https, https and http difference of?
- IP datagram format?
- TCP datagram format?
- UDP datagram format?
- Ethernet MAC frame format?
- How to determine whether the two hosts connected?
- Brief RIP and how it works.
- Briefly OSPF and how it works.
- Brief BGP and how it works.
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Description of DNS domain name system and how it works.
The DNS: Domain the Name System, the domain name system, the Internet naming system is used for ease of converting people to use the machine name to an IP address.
As shown above, m.xyz.com y.abc.com need to find the IP address:
Host m.xyz.com recursive query to the local name server.
General recursive queries when the query to the local name server host.
- Recursive query : If the local domain name server is the IP address of the domain name is not required, the local domain name server on the customer's way to research to other root name servers, rather than host their own inquiries.
Generally uses an iterative query the local domain name server queries to other root name servers.
- Iterative query: When a root name server receives a request packet local domain name server, or tell it the IP address of the desired domain name, or tell it to the next step should launch an inquiry to which server. Then let the local domain name server queries themselves.
Iterative query the local domain name server, first in one root name server queries.
Root name server told local domain name server, the next step should be to query the top-level domain name server dns.com.
Top-level domain server dns.com told local domain name server, domain name server authority to find the next step: dns.adc.com.
Local domain name server sends a query to a domain name server authority. Tell the local domain name server authority required server's IP address, telling the local server to the local host.
Supplement - Classification name server:
Root name server: the highest level and most important domain name server, all domain name root name servers know the addresses of all the top-level domain server and IP address . For example: a.rootserver.net.
Top-level domain servers: all these secondary domain name server is responsible for managing registered on the top-level domain servers. For example: com
Domain Name Server permissions: responsible for domain name server for a zone, if the current domain name server authority can not give the required IP address, which is returned to the client should look for a rights server.
Local domain name server: local DNS DNS that generally refers to when the Internet to fill in IPv4 or IPv6 settings of your computer. This might be manually assigned or automatically assigned DHCP. When a host sends a DNS request, the query message is sent to the local domain name server.
Description of the HTTP protocol and how it works.
HTTP is a transaction-oriented (transaction-oriented) application layer protocol, it is possible to reliably exchange files on the World Wide Web (including text, sound, images and other multimedia files) of the important basis.