Analysis of Vsftpd fault solutions in Linux (Part 1)

After collecting and sorting out relevant linux Vsftpd server troubleshooting materials, I would like to recommend this article here. Due to the long length, I have divided the previous article and the next article. I hope you will have a lot to learn.

In the VSFTPd server, Vs indicates "Very secure ". From the name, we can see that the software developers pay great attention to their security. According to official website data, a linux VSFTPd server can support up to 1500 concurrent users. TB data can be stored within 24 hours. Before explaining the Vsftpd server troubleshooting method, first understand the file structure of the linux VSFTPd Server:
Configuration File Name Function Description
Main Program of/usr/sbin/VSFTPd
/Etc/rc. d/init. d/VSFTPd Startup Script
/Etc/VSFTPd. conf main configuration file
/Etc/pam. d/VSFTPd PAM Authentication File
/Etc/VSFTPd. ftpusers disable VSFTPd User List Files
/Etc/VSFTPd. user_list prohibit or allow VSFTPd User List Files
/Var/ftp Anonymous user home directory
/Var/ftp/pub anonymous user download directory
/Etc/logrotate. d/VSFTPd. log VSFTPd log File

In addition, there are some instruction documents and manual documents. Understanding log files
Understanding the log file is very important for troubleshooting. Here we will introduce the detailed setting method. Log-related VSFTPd options:
VSFTPd_log_file
Xferlog_enable
Xferlog_std_format
Xferlog_file
Dual_log_enable
Syslog_enable
Log_ftp_protocol
No_log_lock

Before introducing Vsftpd server troubleshooting, let's take a look at the log record parameters in vsftp.
Xferlog_enable = yes/no // whether to enable the xferlog log format
Xferlog_std_format = yes/no // whether logs are recorded in standard format
Xferlog_file =/path/to/logfile // location of the xferlog file. The default value is/var/log/xferlog.

The preceding parameter settings record the xferlog format. This is the log format of the early Wu-ftpd service, which records the upload and download actions. VSFTPd also has a proprietary log format, which is set with the following parameters:
Dual_log_enable = yes/no // whether to use VSFTPd's own logging method

Log_ftp_protocol = yes/no // whether to record all ftp command logs VSFTPd_log_file =/path/to/logfile // specify the location of the VSFTPd log file. The default value is/var/log/VSFTPd. the default value of log and xferlog_enable is changed to yes in the configuration file template provided by noVSFTPd. The default value of dual_log_enable is no, that is, VSFTPd does not record logs by default. We can also write the log information into the system log/var/log/messages, using the following parameters:
Syslog_enable = yes/no
The content of an xferlog file is as follows:
Thu Mar 4 08:12:30 2008 1 202.114.40.242 37/incoming/index.html a _ o a guest @ my.net ftp 0 * c

The following table lists the data parameters of the first row.
Description of Record Data Parameters
Thu Mar 4 08:12:30 2008 Local Time of the current server, format: "ddd mmm dd hh: mm: ss YYYY"
The above is the first article on how to troubleshoot Vsftpd servers in Linux/unix. To be continued.

1. Analyze the differences between the linux make command and Makefile
2. Linux script Shell command
3. Who command for viewing serialization in linux Process
4. Commands for normal shutdown in linux
5. Linux FTP server access permission collector