CentOS, Vsftpd, why doesn't active mode work?

Question

linux

Disabled passive mode, enabled active according to manuals (in vsftpd.conf config):
pasv_enable=NO
port_enable=YES
Next, I restart vsftpd and try to connect.
In the active mode, I connect, I can upload files, read them. Everything is working.
I go up the directories /www/domainname.com/ and then the FTP client hangs and issues:
Timeout detected. Could not retrieve directory
In passive mode, everything works.
If I try in active mode, let's say, go directly to the /www/domainname.com/directory/ directory,
then again everything works. How to get into the folder with the site? Why does such an error occur? chmod put 775 everywhere. Nothing has changed.

Answer 1

Active mode may not work if not supported on the firewall by the client.
For example, for iptables, you need to use the nf_conntrack_ftp module.