How to Fix Authentication Problems on FileZilla Linux — Too many authentication failures

This is for FileZilla on Linux Mint (and probably other Linux), as of September 2023 (FileZilla 3.65.0).

I want to connect securely, so I always use SFTP instead of insecure FTP. You should always use SFTP, or transfer files via an SSH connection. 

FileZilla though doesn’t know how to not send an SSH key if you don’t specify one. 

If you turn on Debug (Edit, Preferences, Debug) you can see what is generating the authentication failures. FileZilla is trying every SSH key you have, even though you didn’t say to send any SSH keys. The server disconnects you after too many attempts. 

What is FileZilla’s Problem?

FileZilla doesn’t know how to send only the SSH keys you specify, to the hosts you try to connect to. Definitely a bug, they should fix that. 

So, every site you attempt to connect to, gets every SSH key in your ~/.ssh folder (or rather, all the ones in the .ppk format FileZilla understands). After too many attempts, the remote server disconnects you. 

How to Fix It?

There are many sites and many questions on FileZilla’s support boards about how to get FileZilla working. The main suggestion is “temporarily move your ~/.ssh folder”. But you would have to do that every time you want FileZilla to connect to your servers that don’t use SSH keys. 

I finally found someone who understood the problem. See the reply by “vincitus” on Not possible to disable SSH public key authentication? – FileZilla Forums

Installing Latest FileZilla

Download the latest version from FileZilla Downloads, since the version in the Mint Repository is ancient.

How to install FileZilla FTP client in Linux | Web Developers Planet 

Make sure you have the  dependencies

sudo apt-get install libfilezilla-dev libwxbase3.0-dev gnutls-dev libdbus-1-dev

You don’t have to compile it, the .xz download file is ready for Linux Mint.

cd ~/Downloads
sudo tar vxf FileZilla_____.xz
[substitute the file name for the version just downloaded]
sudo cp -r FileZilla3 /opt/
cd /opt/
sudo chown -R root:root FileZilla3/

Starting FileZilla (normally)

Put this in your System Menu. (Right-click the “LM” tray icon, Configure, “Menu” tab, “Open the menu editor”, in the Internet section click “New Item”

/opt/FileZilla3/bin/filezilla

Starting FileZilla w/o SSH Keys

Start FileZilla with an Environment Variable mis-set to not access SSH. 

Edit your ~/.bashrc file to add this line (at the end is fine, or with other “alias” lines)

alias fz="SSH_AUTH_SOCK=null  /opt/FileZilla3/bin/filezilla &  "

I called the alias “fz” for “FileZilla”, you can name it how you want (but no spaces in the name). 

What that command does is remove the SSH setting for only this terminal session, and run FileZilla. That ‘&’ at the end says to immediately give you access to the terminal (FileZilla launched in the background). Without the SSH_AUTH_SOCK setting, FileZilla doesn’t know how to access your system’s SSH keys, so it can’t send them to the remote servers you connect to.


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