The latest network engineer interview list in 2023. If you can answer all the questions, you will definitely get an offer.

1. Directory
Both TCP and UDP can realize client/server communication. What is the difference between these two protocols?
Which layer of protocol is it and what is its function?
Please tell me the port numbers of FTP, SSH, TELNET, DNS, HTTP, HTTPS, and SMTP protocols?
Briefly describe what is the TCP three-way handshake?
Which layers does the OSI model include from bottom to top? What are the PDU units on each floor?
What is static routing? What are the characteristics?
Taking Huawei equipment as an example, how to achieve remote management of routers and switches?
What is the role of switch configuration IP? How to configure the management IP of Huawei switches?
What is TTL? What is the function?
When making twisted pair cables, what are the line sequences of T568b and T568a?
Please introduce the OSPF protocol?
OSPF is a link state routing protocol.
OSPF has fast convergence and no loops.
OSPF is suitable for campus networks of medium and large enterprises.
OSPF has five types of packets, which are
the seven common LSAs of OSPF . Briefly
describe the role and working principle of STP?
What is the difference between a switch and a router?
How does VRRP work?
What are the statuses of OSPF neighbor establishment?
Why does OSPF divide areas?
9What is the difference between a Trunk link and an Access link?
Why is OSPF stuck in init state?
Why is OSPF stuck in 2-way state?
Why is OSPF opened in the exstart state?
What does ACL technology refer to? What are its types and their respective characteristics?
Briefly describe the OSPF adjacency formation process and the data packets used? .Comparison
of link state routing protocols and distance vector routing protocols?
Which one in OSPF carries the complete link state packet?
Who mainly generates the LSA type in OSPF?
Why is OSPF not in Full state?
Talk about the difference between BGP routing protocol and IGP routing protocol?
What are the principles of BGP route selection?
Why don't BGP neighbors advertise routes to each other?
BGP split horizon 2. Neighbor-based split horizon
What are Hybrid ports in Huawei switches?
Briefly describe the role and working principle of DHCP?
Under what circumstances is it necessary to deploy a DHCP relay?
What are the benefits of configuring dynamic address acquisition for employee PCs in an enterprise?

Due to space limitations, only some of the questions and answers are shown here. If you need a complete summary of the interview question document, you can privately message "Learn" in the background or leave a comment "I want it" to get it!
2. Reference answers

• Both TCP and UDP can achieve client/server communication. What is the difference between these two protocols?

  1. The TCP protocol is connection-oriented, has high reliability, and is suitable for transmitting large amounts of data; however, it requires three-way handshakes, data resend and other processes, which is time-consuming and has high communication delays.

  2. The UDP protocol is non-connection oriented, has low reliability, and is suitable for transmitting small amounts of data; however, the connection speed is fast, time-consuming, and delay is small.

• What layer of protocol is ARP and what is its role?

  1. ARP stands for Address Resolution Protocol, a three-layer network layer protocol.

  2. Its function is to obtain the physical address based on the IP address and achieve rapid encapsulation of data frames.

• Please tell me the port numbers of FTP, SSH, TELNET, DNS, HTTP, HTTPS, and SMTP protocols?

  1.FTP, File Transfer Protocol (provides file upload/download for clients), TCP21 port (control connection), TCP20 port (data connection)

  2.SSH, Secure Command Line Protocol (providing a secure channel for remote management of devices), TCP22 port

  3.TELNET, remote network terminal protocol (providing an interface for remote management equipment), TCP23

  4.DNS, domain name resolution protocol (implementing "domain name <–>IP address" query), UDP53 port (query), TCP53 port (data synchronization)

  5. HTTP, Hypertext Transfer Protocol (providing web resource transmission interface), TCP port 80

  6. HTTPS, secure hypertext transfer protocol (providing an encrypted transmission interface for web resources), TCP 443 port

  7.SMTP, Simple Mail Transfer Protocol (used to send and deliver emails), TCP25 port

• Briefly describe what is the TCP three-way handshake?

  1.A sends a TCP message, in which the flag bit is SYN and seq=x, which means "requesting to establish a new connection";

  2. After B receives the message sent by A, it responds with a TCP message, in which the flag bits are SYN and ACK, seq=y, ack=x+1 means "confirm that the Seq sequence number of A's message is valid, and data can be sent and received normally. and agree to create a new connection;

  3. After A receives the response, it responds with a TCP message, in which the flag bit is ACK, seq=x+1, ack=y+1, and the connection is successfully established.

• Which layers does the OSI model include from bottom to top? What are the PDU units on each floor?

  1.OSI reference model: physical layer->data link layer->network layer->transport layer->session layer->presentation layer->application layer.

  2. PDU units of each layer: physical layer (bit), data link layer (frame), network layer (packet), and transport layer (segment).

• What is static routing? What are the characteristics?

  1. Static routing is a fixed route manually configured by the administrator in the router. It cannot respond to changes in the network. Therefore, static routing is generally used for networks with small network scale and relatively fixed topology.

  2. Features: precise control of routing paths, simple configuration

• Taking Huawei equipment as an example, how to achieve remote management of routers and switches?

  1. Confirm the IP address of the device (router interface, switch VLAN1)

  2. Enable AAA authentication on the device (enable AAA mode, add user account, allow telnet control)

  3. Telnet the IP address of the device from the client computer and log in to perform management.

  

Due to space limitations, only some of the questions and answers are shown here. If you need a complete summary of the interview question document, you can privately message "Learn" in the background or leave a comment "I want it" to get it!