When I try to connect to a server with FTPS support, passive mode makes transfers hang. Hang happens both over IPv4 and IPv6. The connection status shows as "ESTABLISHED" in netstat on both sides. The problem doesn't occur without AUTH TLS, works over both IPv4 and IPv6. The problem doesn't occur with active mode neither, works over both IPv4 and IPv6.
Server: ProFTPD 1.3.5, configured for FTPS
The client is on the same network with the server, no firewall between them.
FileZilla can transfer encrypted data in passive mode without problems.
Steps to Reproduce:
1. Server with FTPS.
2. ftp -p
Connected to [...].
220 ProFTPD 1.3.5 Server [...]
Name [...]: ****
234 AUTH SSL successful
[SSL Cipher ECDHE-RSA-AES256-GCM-SHA384]
331 Password required for ****
230 User **** logged in
Remote system type is UNIX.
Using binary mode to transfer files.
227 Entering Passive Mode ([...]).
150 Opening ASCII mode data connection for file list
Shouldn't hang. FileZilla can connect without problems.