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If you were connected via FTP and suddenly lost access, your IP was likely blocked by the server firewall due to too many connections, failed authentication attempts, or a timeout that triggered brute-force protection. This is a temporary block and is easy to resolve.
Unblock your IP and reduce connections
Use the Firewall Unblock tool to remove the block. Then reduce your FTP client's concurrent connections to 2-3 and increase the timeout to prevent it from happening again.
01. Unblocking Your IP
Follow the steps in our firewall unblock guide to remove your IP from the block list. You can also check if your IP is blocked using upordown.ultrawebhosting.com. If the server is up for everyone else but not for you, your IP is likely blocked.
Before reconnecting after an unblock, make sure your FTP client has the correct password. If your client has cached an old password, every reconnection attempt counts as a failed login, and your IP will be blocked again within seconds.
02. Why This Happens
The server firewall (CSF) monitors all incoming connections and automatically blocks IPs that trigger brute-force detection rules. Common FTP triggers:
Too many simultaneous connections - FTP clients default to 5-10 concurrent connections. The firewall sees this burst of connections from a single IP and interprets it as a potential attack. FileZilla's default is 10, which is too high.
Failed login attempts - A wrong password, a typo in the username, or a cached expired password triggers failed auth logs. Five consecutive failures typically result in a block.
Rapid reconnection - If your connection drops and the client immediately tries to reconnect with multiple threads, each retry counts as a new connection attempt. The burst can trigger the block.
Session timeout - If your connection goes idle and times out, some FTP clients aggressively try to reconnect with multiple threads simultaneously.
03. Preventing Future Blocks
Configure your FTP client with these settings to avoid triggering the firewall:
FileZilla: Go to Edit > Settings > Transfers. Set "Maximum simultaneous transfers" to 2. Under Connection > set "Timeout" to 60 seconds. See our FileZilla connections guide.
SmartFTP: Go to Tools > Settings > Transfer > set concurrent connections to 2. See our SmartFTP connections guide.
Any FTP client: Keep concurrent connections at 2-3, set timeout to 60 seconds, and enable passive mode.
04. Using SFTP Instead
SFTP (SSH File Transfer Protocol) is more reliable than FTP for ongoing file management. It uses a single connection on port 22, which is less likely to trigger firewall rules. Most FTP clients (including FileZilla) support SFTP - just change the protocol to SFTP and the port to 22.
For detailed SFTP setup instructions, see our FTP client guide and SSH access guide.
Keep Getting Blocked?
If your IP keeps getting blocked during FTP sessions despite reducing connections, open a ticket and we can investigate or whitelist your IP.
Open a Support TicketQuick Recap: FTP Access Blocked
- Use the Firewall Unblock tool to remove the block
- Reduce connections to 2-3 in your FTP client settings
- Increase timeout to 60 seconds
- Verify your password before reconnecting to avoid re-triggering
- Consider SFTP on port 22 for more reliable connections
Last updated March 2026 · Browse all FTP articles
