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列出目录内容时，vsftpd 使用代码 421 关闭连接

tag-icon • tag-icon arch-linux ftp vsftpd
列出目录内容时，vsftpd 使用代码 421 关闭连接

我目前正在努力解决 vsftpd 的某种连接问题。

我使用的是 arch linux 并安装了 vsftpd 版本 3.0.3。

我不使用 iptables 或任何东西。当我连接到 FTP 服务器时，我可以成功登录并浏览目录。我还可以上传和下载文件。

FTP 用户被chroot 到其主目录中，并且所有子目录都归ftp 用户所有。

目前的结构：

|- home_dir
   |- dir1
      |- dir2
         |- dir3
         |- dir3
         |- dir4
         |- ...

我可以“cd”进入 dir1，执行“ls”并上传/下载文件。我也可以“cd”到 dir2，但棘手的部分来了：

我可以完美地将文件上传到 dir2，但是当我执行“ls”时，服务器正在关闭连接，并显示：“421 服务不可用，远程服务器已关闭连接”。我发现，原因是“dir2”的几个子目录。我发现，所有子目录中 8 个的存在导致连接被关闭。一旦我删除它们，列表就可以正常工作。所有名称均包含从 a 到 z 的小写字母，没有特殊字符。

我的 ftp 配置：

log_ftp_protocol=YES
anonymous_enable=NO

userlist_enable=YES
userlist_file=/etc/vsftpd.user_list
userlist_deny=NO

pasv_addr_resolve=YES
pasv_address=mydomain.com
pasv_enable=Yes
pasv_min_port=40020
pasv_max_port=40030

local_enable=YES

write_enable=YES

local_umask=002

dirmessage_enable=YES

xferlog_enable=YES

connect_from_port_20=YES


chown_uploads=YES
chown_username=myuser


ftpd_banner=Welcome.

chroot_local_user=YES

这就是服务器 FTP-Log 所说的：

Wed Dec 28 13:55:06 2016 [pid 2] CONNECT: Client "<client_ip>"
Wed Dec 28 13:55:06 2016 [pid 2] FTP response: Client "<client_ip>", "220 Welcome."
Wed Dec 28 13:55:07 2016 [pid 2] FTP command: Client "<client_ip>", "USER myuser"
Wed Dec 28 13:55:07 2016 [pid 2] [myuser] FTP response: Client "<client_ip>", "331 Please specify the password."
Wed Dec 28 13:55:07 2016 [pid 2] [myuser] FTP command: Client "<client_ip>", "PASS <password>"
Wed Dec 28 13:55:07 2016 [pid 1] [myuser] OK LOGIN: Client "<client_ip>"
Wed Dec 28 13:55:07 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "230 Login successful."
Wed Dec 28 13:55:07 2016 [pid 3] [myuser] FTP command: Client "<client_ip>", "OPTS UTF8 ON"
Wed Dec 28 13:55:07 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "200 Always in UTF8 mode."
Wed Dec 28 13:55:07 2016 [pid 3] [myuser] FTP command: Client "<client_ip>", "PWD"
Wed Dec 28 13:55:07 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "257 "/" is the current directory"
Wed Dec 28 13:55:07 2016 [pid 3] [myuser] FTP command: Client "<client_ip>", "TYPE I"
Wed Dec 28 13:55:07 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "200 Switching to Binary mode."
Wed Dec 28 13:55:07 2016 [pid 3] [myuser] FTP command: Client "<client_ip>", "PASV"
Wed Dec 28 13:55:07 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "227 Entering Passive Mode (<server_ip>,156,86)."
Wed Dec 28 13:55:07 2016 [pid 3] [myuser] FTP command: Client "<client_ip>", "LIST"
Wed Dec 28 13:55:07 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "150 Here comes the directory listing."
Wed Dec 28 13:55:08 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "226 Directory send OK."
Wed Dec 28 13:55:09 2016 [pid 3] [myuser] FTP command: Client "<client_ip>", "CWD /dir1"
Wed Dec 28 13:55:09 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "250 Directory successfully changed."
Wed Dec 28 13:55:09 2016 [pid 3] [myuser] FTP command: Client "<client_ip>", "PASV"
Wed Dec 28 13:55:09 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "227 Entering Passive Mode (<server_ip>,156,92)."
Wed Dec 28 13:55:09 2016 [pid 3] [myuser] FTP command: Client "<client_ip>", "LIST"
Wed Dec 28 13:55:09 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "150 Here comes the directory listing."
Wed Dec 28 13:55:09 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "226 Directory send OK."
Wed Dec 28 13:55:11 2016 [pid 3] [myuser] FTP command: Client "<client_ip>", "CWD /dir1/dir2"
Wed Dec 28 13:55:11 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "250 Directory successfully changed."
Wed Dec 28 13:55:11 2016 [pid 3] [myuser] FTP command: Client "<client_ip>", "PASV"
Wed Dec 28 13:55:11 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "227 Entering Passive Mode (<server_ip>,156,87)."
Wed Dec 28 13:55:11 2016 [pid 3] [myuser] FTP command: Client "<client_ip>", "LIST"
Wed Dec 28 13:55:11 2016 [pid 3] [myuser] FTP response: Client "<client_ip>", "150 Here comes the directory listing."

日志始终在“150 Here comes the Directory Listing.”之后停止。我试了几次。

当我在终端上使用 ftp 命令时，我看到的是：

$ ftp -n 127.0.0.1

Connected to 127.0.0.1.
220 Welcome.
ftp> user myuser
331 Please specify the password.
Password:
230 Login successful.
ftp> ls
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
drwxr-xr-x    4 1000     1000         4096 Dec 28 13:27 dir1
226 Directory send OK.
ftp> cd dir1
250 Directory successfully changed.
ftp> ls
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
-rwxr-xr-x    1 1000     1000       469504 Dec 23 03:03 file_1
-rw-r--r--    1 1000     1000          186 Feb 19  2016 file_2
-rw-r--r--    1 1000     1000       121856 Dec 23 00:16 file_3
-rw-r--r--    1 1000     1000       118272 Feb 12  2016 file_4
-rw-r--r--    1 1000     1000        88232 Mar 22  2016 file_5
-rw-r--r--    1 1000     1000        64680 Mar 22  2016 file_6
-rw-r--r--    1 1000     1000       101032 Mar 22  2016 file_7
-rw-r--r--    1 1000     1000         6144 Mar 22  2016 file_8
-rw-r--r--    1 1000     1000       899584 Mar 22  2016 file_9
drwxrwxr-x   42 1000     1000         4096 Dec 28 11:38 dir2
226 Directory send OK.
ftp> cd dir2
250 Directory successfully changed.
ftp> pwd
257 "/dir1/dir2" is the current directory
ftp> ls
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
421 Service not available, remote server has closed connection

非常感谢您的帮助。

答案1

我解决了目录列表因超过 10 个文件而失败的问题（如克里斯蒂安·蒙德）通过添加这个

seccomp_sandbox=NO

到/etc/vsftpd.conf

来源拱门维基

答案2

我也遇到了完全相同的问题，也是在带有 vsftp 3.0.3 (pkg rel 3) 的 Arch Linux 上。事实证明，导致此行为的目录中的文件过多 (2,666)。删除其中大部分后，通过 ftp 列出的列表再次开始工作。

很奇怪吧？ 2,666 看起来并不算太多。但我确实没有改变任何其他事情。 vsftp 设置仍然相同，文件系统权限未受影响。此外，文件名不包含任何奇怪的字符（长度最多为 21 个字符的连续数字）。

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