Linux下使用docker 拉取 vsftpd 镜像搭建 Ftp 服务器，连接 Ftp 时遇到的错误（425 Failed to establish connection）

Posted 2022-07-12 grey-wolf

Ftp踩坑系列：

Linux上的ftp服务器 vsftpd 之配置满天飞--设置匿名用户访问(不弹出用户名密码框）以及其他用户可正常上传

ftp服务器Serv-U 设置允许自动创建不存在的目录

FTP协议的粗浅学习--利用wireshark抓包分析相关tcp连接

 

一、前言

出现这个问题，在docker这类容器出现之前，原因可能是防火墙的问题：

FTP服务器一般默认使用被动模式，即，客户端一般会和服务端的21端口建立连接，该连接用来传输命令。真正传输数据时，服务端会返回一个随机端口，告诉客户端新建连接去连接这个随机端口，来传输数据。

一般来说，这个随机端口，肯定是没在防火墙里配置的，所以会无法建立连接。

此时，直接先关掉防火墙即可。

 

二、docker场景下，该问题的解决方案

现在容器越发流行，基于docker构建各类服务显得更加方便。但是，一不注意，还是会踩坑的。

昨天，同事就是遇到这么个问题，说是能连上，但是涉及到数据就看不到，比如查看目录等。

一开始，也怀疑是防火墙的问题，于是直接把防火墙关了，发现问题依旧。

 

后来经过一番定位，发现是vsftpd是基于docker的，其启动docker容器的命令如下：

docker run -d -v /my/data/directory:/home/vsftpd -v /var/log/vsftpd/:/var/log/vsftpd/ -p 20:20 -p 21:21 -p 21100-21110:21100-21110 -e FTP_USER=ROOT -e FTP_PASS=ROOT -e PASV_MIN_PORT=21100 -e PASV_MAX_PORT=21110 -e PASV_ADDRESS=0.0.0.0 -e LOG_STDOUT=1 --name vsftpd --restart=always fauria/vsftpd

 

注意以上红色部门，指定了各类端口相关的配置。

为了快速查找问题，停止了旧的容器后，用下面的命令重新起了个容器，（直接改成了使用宿主机的网络）：

docker run -d -v /my/data/directory:/home/vsftpd -v /var/log/vsftpd/:/var/log/vsftpd/  --network=host -e FTP_USER=ROOT -e FTP_PASS=ROOT  -e LOG_STDOUT=1 --name vsftpd1.1 --restart=always fauria/vsftpd

 

进行了上述的修改后，问题解决了。

具体原因还需要查找，找到了再更新。

 

三、基于docker构建vsftpd容器，相关配置

 

其中，DockerFile：

FROM centos:7
MAINTAINER jason2019
RUN yum install -y vsftpd
#RUN mkdir -p /data/ftp
RUN useradd -d /data/ftp -s /bin/bash ROOT -p ROOT
RUN echo "ROOT:ROOT" | chpasswd
RUN chmod 755 /data/ftp
EXPOSE 20 21
ENTRYPOINT /usr/sbin/vsftpd && tail -f /etc/passwd
#RUN systemctl start vsftp.service

 

其中，operation.txt：

docker build -t ftp:1.0 .
docker run -dit -p 21:21 -p 20:20 -p 21100-21110:21100-21110 -v /data/vsftpd.conf:/etc/vsftpd/vsftpd.conf -v /data/ftp:/data/ftp --name ftp ftp:1.0

如果使用宿主机网络，可以像这样：
docker run -d -v /my/data/directory:/home/vsftpd -v /var/log/vsftpd/:/var/log/vsftpd/  --network=host -e FTP_USER=ROOT -e FTP_PASS=ROOT  -e LOG_STDOUT=1 --name vsftpd1.1 --restart=always fauria/vsftpd

 

其中，vsftpd.conf（支持匿名上传、下载等，为啥要匿名，因为业务的变态需求呗）：

# Example config file /etc/vsftpd/vsftpd.conf
#
# The default compiled in settings are fairly paranoid. This sample file
# loosens things up a bit, to make the ftp daemon more usable.
# Please see vsftpd.conf.5 for all compiled in defaults.
#
# READ THIS: This example file is NOT an exhaustive list of vsftpd options.
# Please read the vsftpd.conf.5 manual page to get a full idea of vsftpd‘s
# capabilities.
#
# Allow anonymous FTP? (Beware - allowed by default if you comment this out).
anonymous_enable=YES

#https://blog.csdn.net/bluishglc/article/details/42399439
allow_writeable_chroot=YES
#
# Uncomment this to allow local users to log in.
local_enable=YES
#
# Uncomment this to enable any form of FTP write command.
write_enable=YES
#
# Default umask for local users is 077. You may wish to change this to 022,
# if your users expect that (022 is used by most other ftpd‘s)
local_umask=022
#
# Uncomment this to allow the anonymous FTP user to upload files. This only
# has an effect if the above global write enable is activated. Also, you will
# obviously need to create a directory writable by the FTP user.
anon_upload_enable=YES
#
# Uncomment this if you want the anonymous FTP user to be able to create
# new directories.
anon_mkdir_write_enable=YES
anon_other_write_enable=YES
#
# Activate directory messages - messages given to remote users when they
# go into a certain directory.
dirmessage_enable=YES
#
# The target log file can be vsftpd_log_file or xferlog_file.
# This depends on setting xferlog_std_format parameter
xferlog_enable=YES
#
# Make sure PORT transfer connections originate from port 20 (ftp-data).
connect_from_port_20=YES
#
# If you want, you can arrange for uploaded anonymous files to be owned by
# a different user. Note! Using "root" for uploaded files is not
# recommended!
#chown_uploads=YES
#chown_username=whoever
#
# The name of log file when xferlog_enable=YES and xferlog_std_format=YES
# WARNING - changing this filename affects /etc/logrotate.d/vsftpd.log
#xferlog_file=/var/log/xferlog
#
# Switches between logging into vsftpd_log_file and xferlog_file files.
# NO writes to vsftpd_log_file, YES to xferlog_file
xferlog_std_format=YES
#
# You may change the default value for timing out an idle session.
#idle_session_timeout=600
#
# You may change the default value for timing out a data connection.
#data_connection_timeout=120
#
# It is recommended that you define on your system a unique user which the
# ftp server can use as a totally isolated and unprivileged user.
#nopriv_user=ftpsecure
#
# Enable this and the server will recognise asynchronous ABOR requests. Not
# recommended for security (the code is non-trivial). Not enabling it,
# however, may confuse older FTP clients.
#async_abor_enable=YES
#
# By default the server will pretend to allow ASCII mode but in fact ignore
# the request. Turn on the below options to have the server actually do ASCII
# mangling on files when in ASCII mode.
# Beware that on some FTP servers, ASCII support allows a denial of service
# attack (DoS) via the command "SIZE /big/file" in ASCII mode. vsftpd
# predicted this attack and has always been safe, reporting the size of the
# raw file.
# ASCII mangling is a horrible feature of the protocol.
#ascii_upload_enable=YES
#ascii_download_enable=YES
#
# You may fully customise the login banner string:
#ftpd_banner=Welcome to blah FTP service.
#
# You may specify a file of disallowed anonymous e-mail addresses. Apparently
# useful for combatting certain DoS attacks.
#deny_email_enable=YES
# (default follows)
#banned_email_file=/etc/vsftpd/banned_emails
#
# You may specify an explicit list of local users to chroot() to their home
# directory. If chroot_local_user is YES, then this list becomes a list of
# users to NOT chroot().
#chroot_local_user=YES
#chroot_list_enable=YES
# (default follows)
#chroot_list_file=/etc/vsftpd/chroot_list
#
# You may activate the "-R" option to the builtin ls. This is disabled by
# default to avoid remote users being able to cause excessive I/O on large
# sites. However, some broken FTP clients such as "ncftp" and "mirror" assume
# the presence of the "-R" option, so there is a strong case for enabling it.
#ls_recurse_enable=YES
#
# When "listen" directive is enabled, vsftpd runs in standalone mode and
# listens on IPv4 sockets. This directive cannot be used in conjunction
# with the listen_ipv6 directive.
listen=YES
#
# This directive enables listening on IPv6 sockets. To listen on IPv4 and IPv6
# sockets, you must run two copies of vsftpd with two configuration files.
# Make sure, that one of the listen options is commented !!
#listen_ipv6=YES

pam_service_name=vsftpd
userlist_enable=YES
tcp_wrappers=YES
anon_root=/data/ftp
no_anon_password=YES
local_root=/data/ftp
ftp_username=ROOT
pasv_enable=YES
pasv_min_port=21100
pasv_max_port=21110

 

其中，具体的选项名称，可参考:

Linux上的ftp服务器 vsftpd 之配置满天飞--设置匿名用户访问(不弹出用户名密码框）以及其他用户可正常上传

 

另外，匿名上传之类的话，一般还涉及到对根目录的权限的修改，简单起见，直接修改为777：

 

 

 

四、总结

总体来说，配置还是很繁杂的，有问题可以直接加我咨询。