Virtual machine VMware Network type &&SSH remote connection Linux

Introduction : The topic of Linux was written in November 16, said ashamed, has not learned Linux for 5 months, so far feel even the introduction has not reached. Summer internship has to invest and maintenance development post, helpless to Linux unfamiliar, school recruit resume was also brushed. So, I'm going to take 1 months to get into the door. A few days ago also dedicated to Dangdang bought a "with the old boy learn Linux operation and maintenance-web cluster combat." Lenrning begin!!

One, the virtual machine network type

Choosing a network type for a virtual machine is extremely critical. the network types common to VMware virtual machines are bridged (bridged), NAT, Host-only (host only), 3 . When you create a Linux virtual machine, you will be asked to choose a network type. At that time I was very confused, because of these three kinds are not very understanding.

Nat

Nat (network address translation ), Nat mode is a relatively simple way to implement virtual machine access. That is, a virtual machine in NAT mode is connected to the Internet and exchanging data via a host (physical computer) .

In NAT mode, the network card of the virtual machine is connected to the host's VMnet8. At this point the system's VMware NAT Service serves as a router that sends the virtual machine to the VMNET8 package for address translation and sends it to the actual network, then addresses the packets returned on the actual network and sends them to the virtual machine via VMNET8. VMware DHCP Service is responsible for assigning IP addresses to virtual machines.

Advantages and Disadvantages: The NAT network is suitable for the home computer directly connected to the network cable, the advantage is not with other physical host IP conflicts, change the network environment virtual machine IP, etc. unaffected. Highly Recommended!!

Bridged (bridging mode)

Bridging mode is simply understood to be a bridge built through a physical host card to connect to the actual network . Therefore, a virtual machine can be assigned a separate IP with the same network segment as the physical host, and all network functions are almost identical to the real machines in the network.

In bridged mode, a computer device creates a virtual machine that, like a real computer, connects directly to the actual network, and logically has no connection to the host (computer device).

Advantages and Disadvantages: Bridged is suitable for LAN environment, the advantage is that the virtual machine is like a real host, the disadvantage is that it may conflict with other physical host IP, and when the host Exchange data, it will go through the actual router. The IP of all virtual machines will be affected when the network environment is changed in bridged mode .

Host-only (host only)

In host-only mode, the network card of the virtual machine is connected to the host's VMnet1, but the host system does not provide any routing services for the virtual machine, so the virtual machine can only communicate with the host , and cannot connect to the actual network, i.e., the Internet is not available.

Second, SSH remote connection Linux

In almost all Internet enterprise environments, the most common tool for providing Linux remote Connection service is SSH software, SSH isdivided into SSH client and SSH server . The SSH server side contains software programs mainly OpenSSH and OpenSSL. OpenSSH is a program that provides SSH services, and OpenSSL is a program that provides connection encryption for SSH . To query the installation of the SSH server-side tool:

Daemon Process-sshd

By default, the SSH server program is started with the system. The SSH server-side process named sshd is a daemon (daemon) that is permanently running in the background of the system and responds to all connection requests from the SSH client and is processed . These requests typically include public key authentication, key exchange, symmetric key encryption, and unsecured connections.

SSH protocol

This communication between the SSH server and the SSH client is implemented through the ssh (Secure Shell Protocol) protocol. Before the data transfer,SSH encrypts the online data packets by encryption technology, and then transmits the data, so as to ensure the security of the transmitted information. PS: Interested to see the information security topics I wrote

In the current production environment, the majority of enterprises generally use the SSH protocol service to replace the traditional insecure remote online services software, such as Telnet (23 port, non-encrypted)

Upload and download

First you perform RZ, if you have not installed the Rz&sz, you can download by the following command:

Yum Install Lrzsz-y

SECURECRT does not have a graphical file transfer tool, but it does not affect, with the command to achieve, in fact, will be more convenient and fast.

Upload a file simply enter the command "RZ" in the shell terminal emulator to select the file on the local disk from the popup dialog and upload it to the current path of the server using Zmodem .

Download file simply enter the command "SZ file name" in the shell terminal emulator to download the file to a local directory using Zmodem . The directory that is downloaded to the local can be set:

OK, next look: I uploaded the password. txt file to the Linux server, then downloaded the from_windows.py file from the Linux service to the local Windows system

Download Successful:

Virtual machine VMware Network type &&SSH remote connection Linux