Fix FileZilla 421 Too Many Connections Error - Enable Connection Persistence

Error: 421 too many connections (8) from this IP

The "421 too many connections (8) from this IP" error occurs when FileZilla exceeds the server's limit for simultaneous connections from a single IP address. Enabling Connection Persistence can help by reusing the same connection for multiple transfers instead of opening new connections for each action.

This error is specific to FTP/SFTP connections and often appears when transferring multiple files simultaneously or when multiple FileZilla instances are running.

What is Connection Persistence?

Persistent Connections keep a single connection open for multiple commands or file transfers.
This avoids the need to repeatedly open and close connections, which can trigger the server's connection limit.

How to Enable Connection Persistence in FileZilla

Adjust the Simultaneous Connection Limit

Open FileZilla Settings:
- Go to Edit > Settings (Windows/Linux) or FileZilla > Preferences (Mac).
Navigate to Transfers:
- In the settings menu, click on Transfers.
Reduce Maximum Simultaneous Transfers:
- Set the Maximum simultaneous transfers to 2 or 3 (default is often higher).
- Example: Maximum Simultaneous Transfers: 2
Save Changes:
- Click OK to save your settings.

Limit Connections Per Server

Open Site Manager:
- Go to File > Site Manager.
Select Your Server:
- Choose the FTP site/server causing the issue.
Set Connection Limits:
- Go to the Transfer Settings tab.
- Check Limit number of simultaneous connections.
- Set the limit to 2 or 3.
Save and Connect:
- Click OK to save the configuration and reconnect to the server.

Enable Keep-Alive

Go to Settings:
- Navigate to Edit > Settings.
Enable Keep-Alive Commands:
- Under Connection, check the box for Send keep-alive commands.
- This ensures the connection remains open during idle periods.
Save Changes:
- Click OK to apply the settings.

Server-Side Adjustments (If You Manage the Server)

Increase Max Connections per IP

For vsftpd or other FTP servers:

Edit the FTP configuration file:
sudo nano /etc/vsftpd.conf
Adjust the max_per_ip setting:
```
max_per_ip=10
```
Restart the FTP server:
sudo systemctl restart vsftpd

Use Passive Mode

Ensure your server supports Passive Mode, as it reduces simultaneous connection issues by using dynamic ports.

Preventive Measures

Use a Static IP: If you're on a shared IP, switching to a static IP may reduce connection conflicts.
Limit Concurrent Sessions: Avoid running multiple FileZilla instances or sessions from the same machine.
Monitor Server Logs: For server admins, check logs for excessive connections and adjust limits accordingly.

Summary

Enabling connection persistence in FileZilla, reducing simultaneous connections, and optimizing your client settings can resolve the "421 too many connections" issue. If the problem persists, coordinate with your hosting provider or server administrator to increase connection limits.

FileZilla 421 Too Many Connections (8) From This IP - Enable Connection Persistence

What is Connection Persistence?

How to Enable Connection Persistence in FileZilla

Adjust the Simultaneous Connection Limit

Limit Connections Per Server

Enable Keep-Alive

Server-Side Adjustments (If You Manage the Server)

Increase Max Connections per IP

Use Passive Mode

Preventive Measures

Summary

Hosting

Cloud Solution

For You

VDS

Website Builders

Our services

Client Area

Select Currency

FileZilla 421 Too Many Connections (8) From This IP - Enable Connection Persistence

What is Connection Persistence?

How to Enable Connection Persistence in FileZilla

Adjust the Simultaneous Connection Limit

Limit Connections Per Server

Enable Keep-Alive

Server-Side Adjustments (If You Manage the Server)

Increase Max Connections per IP

Use Passive Mode

Preventive Measures

Summary

Hosting

Cloud Solution

For You

VDS

Website Builders

Our services

Client Area

Выберите валюту