In this article, you will learn Linux vsftpd interview questions & answers.
The vsftpd is the daemon of the FTP server. The VSFTP stands for a very secure file transfer protocol. It provides the downloading and uploading files to the FTP server space. So, let’s discuss important interview questions and answers.
Q1: What is vsftpd?
Answer: VSFTPD stands for Very Secure File Transfer Protocol Daemon. Generally, we use FTP to transfer files between computers on a network. The FTP functions are used to open, log in, and close connections, as well as upload, download, rename, delete, and get information on files from file servers.
Q2: What is the default port number for FTP?
Answer: The default or standard port number for FTP in Linux is 20 and 21. But, port 20 is used for data transfer between server and client. And port 21 is used for connection establishment control between server and client. So, All the commands send by the client and response come from the server will go over port 21.
Q3: What is the configuration file of vsftpd?
Answer: The configuration file for vsftpd in Linux located at /etc/vsftpd/vsftpd.conf.
Q4: How to disable standard vsftpd xferlog log format and enable default vsftpd log?
Answer: If you want to disable vsftpd xferlog and enable log for vsftpd.log then you have to change the configuration file settings, Edit the file /etc/vsftpd/vsftpd.conf file with any file editors like vi or vim.
and look for the xferlog_std_format and put it NO and log_ftp_protocol and put YES. the format will look like below,
xferlog_std_format=NO
log_ftp_protocol=YES
After changing the above value, the default vsftpd log file will be /var/log/vsftpd.log.
Q5: What is the Max_clients parameter in ftp?
Answer: This is the parameter that defines how many users can connect at a single time. So, if it set to 0 then the number of clients can be unlimited.
Q6: How can we monitor clients who are connected to the vsftpd?
Answer: There are two different methods to monitor the vsftpd clients. Firstly, you have to enable the config option, setproctitle_enable=YES.
Secondly, after enabling it, restart the vsftpd service. Now you can run the below command to watch the process. It includes ip, username, and actions like idle or data transfer.
watch ps -C vsftpd -o user,pid,stime,cmd
Q7: Local users are not able to log in. How to fix this issue?
Answer: This issue comes when the parameter local_enable is not set to YES in configuration file /etc/vsftpd/vsftpd.conf.
So, to fix this problem enable this parameter to allow the local users. The parameter must be set as the below in the configuration file /etc/vsftpd/vsftpd.conf.
local_enable=YesQ8: What is the default directory for FTP Anonymous users?
Answer: The default directory for ftp anonymous user is /var/ftp/pub/.
Q9: How to change the default directory for FTP anonymous users?
Answer: To change the default directory for anonymous users in FTP, open the /etc/vsftpd/vsftpd.conf file with any editors and then change the directory with the below format,
anon_root=/<Absolute_Path-of-New-Directory>
Q10: How can you restart the vsftp service?
Answer: You can use the below command to restart the vsftpd service.
For CentOS/RHEL 6, Fedora, and Ubuntu
sudo service vsftpd restart
For CentOS/RHEL 7, Fedora, and the latest Ubuntu. Also on OpenSUSE, you can use the below command.
sudo systemctl restart vsftpd
Q11: What is directive session_support in vsftpd?
Answer: This is the parameter that helps to maintain a login session for each user through the Pluggable Authentication Module (PAM).
Q12: What FTP program can I use to send and receive files?
Answer: There are many ftp clients to send and receive files. So, some of them listed below.
- WinSCP
- Filezilla
- CuteFTP
- SmartFTP
- Internet Explorer
Q13: How can you allow the anonymous FTP user?
Answer: You can allow or disallow the anonymous ftp user in the configuration file /etc/vsftpd/vsftpd.conf. So, if you want to allow, then you can change the value of the parameter anonymous_enable toYES. But, if you want to disable it then you can change the value of anonymous_enable to NO.
Q14: List the package name to install vsftpd service in CentOS/RHEL/Fedora/Ubuntu/Debian and OpenSUSE?
Answer: The package name is vsftpd.
Firstly, if you want to install on CentOS/RHEL, use the below command.
sudo yum install vsftpd
Secondly, if you want to install on Fedora, you can use the below command.
sudo dnf install vsftpd
Thirdly, you can install on Ubuntu/Debian using the below command.
sudo apt install vsftpd
Lastly, you can use the below command to install on OpenSUSE.
sudo zypper in vsftpd
Conclusion
In this article, you learned about vsftpd interview questions and answers. So, I hope you understand, but if you have any questions, you can ask in the comment section.
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