FTP

FTP 200 Command OK vs 426 Connection Closed

FTP 200 (Command OK) is a 2xx Positive Completion response, while 426 (Connection Closed) is a 4xx Transient Negative response. 200 indicates that the command has been successfully executed. This is a general acknowledgment that the command was understood and carried out. In contrast, 426 means that connection closed; transfer aborted. The data connection was closed unexpectedly during a file transfer.

Description

The command has been successfully executed. This is a general acknowledgment that the command was understood and carried out.

When You See It

After issuing any command that completes successfully, such as TYPE, MODE, or NOOP.

How to Fix

No fix needed — the command succeeded. This is the standard positive response for commands that don't return data.

Description

Connection closed; transfer aborted. The data connection was closed unexpectedly during a file transfer.

When You See It

When a file transfer is interrupted due to a network timeout, client disconnect, or the data connection dropping mid-transfer.

How to Fix

Retry the transfer. If it keeps failing, check network stability, increase timeout values, and verify there are no firewalls killing idle connections.

Key Differences

1.

200 is a 2xx Positive Completion response, while 426 is a 4xx Transient Negative response.

2.

FTP 200: The command has been successfully executed. This is a general acknowledgment that the command was understood and carried out.

3.

FTP 426: Connection closed; transfer aborted. The data connection was closed unexpectedly during a file transfer.

4.

You encounter 200 when after issuing any command that completes successfully, such as TYPE, MODE, or NOOP.

5.

You encounter 426 when when a file transfer is interrupted due to a network timeout, client disconnect, or the data connection dropping mid-transfer.

When to Use Which

For 200 (Command OK): No fix needed — the command succeeded. This is the standard positive response for commands that don't return data. For 426 (Connection Closed): Retry the transfer. If it keeps failing, check network stability, increase timeout values, and verify there are no firewalls killing idle connections.

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