Resolved FTP Connection Closed By Server

[PeterK900]

Server operating system version

CentOS Linux 7.9.2009 (Core)

Plesk version and microupdate number

18.0.54

I'm trying to connect a domain using FileZilla. Connection is achieved but then rejected by the server. Here are the FileZilla log messages...

Connection established, waiting for welcome message...
Error: Connection closed by server
Error: Could not connect to server

I found this post but I can find no FTP firewall settings on the server, only the Web Application firewall. In the past with a different server, I've had no problem connecting FileZilla to a Plesk server. What am I doing wrong? Thanks.

 

[Peter Debik]

If Plesk Firewall is not installed, please install it from the "Extensions" menu or through Updates/Upgrades as described in

https://support.plesk.com/hc/en-us/articles/12377540171799

 

[PeterK900]

Thanks Peter, but I don't think this is the problem. I configured Firewalls as per your link and left the default rules in place, allowing all from FTP. But the problem remains. And I can connect with FTP without Firewall installation on an almost identical server - same Centos version, Plesk 18.054.

 

[Peter Debik]

In your above post you wrote, you cannot find FTP firewall settings on the server. In the latest post you say that you have the default rules in place. FTP Passive Ports is one of these default rules. If it does not exist, you can follow this guide to create it:

(Plesk for Linux) Configuring Passive FTP Mode

By default, Plesk allows only active FTP connections. This may result in customers being unable to connect to the ser...

docs.plesk.com

 

[PeterK900]

Thanks Peter. Will do.

I've just logged into Plesk via the hosting server panel, rather than directly as I normally do. I see this message...

Server Dashboard Capability Is Limited
This dashboard relies on agent applications running on your server for certain operations to work, called nydus-ex and nydus-ex-api. They work through connections to your server on port 2224. Please ensure your firewall is not blocking this port and that these applications are running. Unblock Ports Required for My Generation 4 Server.

which I think may explain the FTP issue. Because I also cannot connect via SSH either in Plesk or using PuTTy. That's a problem because the link in the above message requires SSH. I've asked the hosting company for advice but if this isn't forthcoming I may need some Plesk Forum help. The other server, where FTP works, displays no Server Dashboard Capability message.

 

[Peter Debik]

Regarding the "Server Dashboard Capability" message I have no further information, because that is not related to Plesk. This is about your data center's configuration only. I think it is about a monitoring or external server control tool that your data center offers. So probably your hosting company is the right place to get this resolved.

 

[PeterK900]

Thanks again.

 

[PeterK900]

An update to complete the story on this...

The ftp problem appears to be part of a bigger issue. Whether related to the nydus-ex and nydus-ex-api issue raised in the Web Host's (Heart Internet) warning message (see #5) I don't know. Shortly after the ftp problem SSH connectivity was lost. Heart support ( this is an unmanaged server ) was unable to offer any explanation or solution. Apparently they can't unblock ports which caused the ftp and SSH connectivity problem. So we moved everything to another server (web hosting continued to work fine) and rebuilt the server. Problem resolved. But it's a shame that an explanation for these problems from the Web Host wasn't forthcoming.