Re: [Proftpd-user] unstable performance connections hang/drop : aborting transfer: Data connection closed

If I connect directly it works really better , or at least I cannot reproduce the hang. 

Maybe it's a mix of firewall and clients with proftpd , I dunno, is there a way to force clients to connect in passive mode? 

Simone 


Da: "Matus UHLAR - fantomas" <[email protected]> 
A: "proftp-user" <[email protected]> 
Inviato: Martedì, 6 settembre 2022 14:44:43 
Oggetto: Re: [Proftpd-user] unstable performance connections hang/drop : aborting transfer: Data connection closed 

On 06.09.22 13:39, Simone Montagnani wrote: 
>I'm writing in seek for help for an issue on one FTP server with Ubuntu 22 LTS and proftpd 1.3.7c just installed from scratch. 
> 
>This server is behind an Enterprise Firewall, and is being installed in place of an old Debian/vsftpd server , same public and private IP. 
>No problem with the old installation that worked for years. 
> 
>The problem is that FTP clients connections are unstable, after a random 
> time, and especially after some activity they just hang. 

this indicates firewall problem. Does this happen when you connecting 
without firewall? 

>I have not specified Masquerade Address at the moment, I tried just for a 
> brief time and I got the same errors. 

MasqueradeAddress is only needed if the firewall does not support FTP or you 
use ftps where you firewall can't see the content of control connection. 
You then need to explicitly forward set of passive ports to FTP server on 
the firewall and set those ports to PassivePorts directive. 

>aborting transfer: Data connection closed 
> 
>I can see in real time on the FTP server ports are opening regularly as 
> they should , at every command I make when logged in , even an "ls" open 
> all the ports in passive "style" . 

>I can reproduce the issue if I login and type for example "ls -l" manually 
> continuously for 20 times, I can see that all ports are opening between me 
> and the server, but after some random time is just stop with the last 
> command and stays there locked. 
> 
>I tried check firewall settings, I cannot find the problem there , FTP is 
> opening ports ok , so it's not a "blocking ftp active/passive issue", but 
> I cannot understand why everything was working fine before with the old 
> server and now it's so unstable. 

one of problems can be caused by using of EPSV/EPRT commands which need to 
be supported in firewall that may already support PASV/PORT. 

-- 
Matus UHLAR - fantomas, [email protected] ; https://eu-west-1.protection.sophos.com?d=fantomas.sk&u=aHR0cDovL3d3dy5mYW50b21hcy5zay8=&i=NWE2OWE2MGM5MGM3OGQxNzlkNzVlMGNj&t=bWRGL08yOTQ1OXBCTXdvSjNra3p3d0dNMWxuYjJxNzZ6L01yWHFNcjlNRT0=&h=5f1bf9cd47b641029ba01a6456cafffb 
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