1. What parts does the URL contain and what does each part do?
A full URL= protocol + domain name or IP+ port number + path + query string + anchor point.
For example: https://www.baidu.com/s?wd=hello&rsv_spt=1#5
- “HTTPS:” is the protocol section, which indicates which protocol the browser must use. The URL indicates that the web page uses THE HTTPS protocol.
- “www.baidu.com” is the domain name part, which indicates which Web server is being requested. In a URL, an IP address can also be used.
- The port is not specified in this URL because HTTPS defaults to port 443.
- /s is the path part, indicating the path of resources on the network server.
- “? Wd = hello&rsV _spt=1 “is the query string. Multiple parameters are allowed in the query string. The parameters are separated by ampersand (&). The query string is an additional parameter provided to the web server.
- “#5” is an anchor point, which represents a “bookmark” in a resource that gives the browser the direction of the content at that “bookmarked” location.
2. What is the function of DNS? How to use nslookup command?
The Domain Name System (DNS) is a hierarchical and decentralized naming System for Internet connection resources. DNS maintains a list of domain names and corresponding resources such as IP addresses.
The most prominent feature of DNS is to translate easy-to-remember domain names (e.g. Mozilla.org) into digital IP addresses (e.g. 151,106,5,172). This mapping of domain names to IP addresses is called a DNS lookup, and a DNS reverse lookup (rDNS) is used to find the domain name corresponding to the IP address.
Using the nslookup command, you can query DNS records to check whether domain name resolution is normal and diagnose network faults. Its usage is as follows:
- Direct query:
nslookup domain [dns-server] - Querying Other Records:
nslookup -qt=type domain [dns-server]
Where, type can be the following types:
- A Address Record
- AAAA address record
- AFSDB Andrew File system database server record
- ATMA ATM address record
- CNAME Alias record
- HINFO Records hardware configurations, including CPU and operating system information
- ISDN ISDN number corresponding to the domain name
- MB The server that stores the specified mailbox
- MG mail group records
- MINFO Mail group and mailbox information records
- The email record of MR’s name change
- MX mail server records
- NS name server records
- PTR Reverse record
- RP Person in charge record
- RT Route penetration record
- SRV Records TCP server information
- TXT Indicates the text information of the domain name
- X.25 address record of domain name X25
- Query more specific information:
Nslookup -d domain [dnS-server]
You can query the domain name cache by adding the -d parameter.
3. What is the function of IP? How does ping work?
IP Address (English: IP Address, full name of Internet Protocol Address), also translated as the Internet Protocol Address, Internet Protocol Address. When the device is connected to the network, the device is assigned an IP address for identification. With IP addresses, devices can communicate with each other. Without IP addresses, we have no way of knowing which device is the sender and which is the receiver. IP addresses have two main functions: identifying devices or networks and addressing (English: Location Addressing).
The ping command is used to check hosts.
After the ping command is executed, ICMP is used to send a message requesting a response. If the remote host is running properly, the remote host responds to the message.
Grammar: ping [- dfnqrRv] [-c < complete number >] [-i number > < seconds] [-i < > network interface] [-l < pre > loaded] [-p < style > model] [-s < > packet size] [-t numerical > < live] [host name or IP address]
4. What is a domain name? What are the types of domain names?
Domain Name (Domain Name for short) is the Name of a computer or computer group on the Internet consisting of a series of characters separated by dots. It is used to identify the electronic location of the computer during data transmission. A domain name is an alternate name for an IP address for easy memorization.
Domain names fall into three main categories:
- The first category is General Top Level Domain (gTLD)
- The second category is country Code Top Level Domain (ccTLD).
- The third category is New Generic Top-level Domains (New gTLD) that have been added since the implementation of the “New Generic Top-level Domains” program in 2011.