The following connection settings are the next most common issues related to SFTP. Please double check all of the following.

Hostname

The hostname should be set to [your_subdomain].files.com or the custom domain for your site, if applicable. Connecting by specifying an IP address may sometimes work, and we do have customers doing this for specific reasons, but it is not officially supported and we are unable to proceed with helping you troubleshoot if you are doing this.

Port

By default, you should be using port 22. However, the port setting is a great way to work around corporate firewalls. The default SSH/SFTP port of 22 is blocked or interfered with by many corporate firewalls. You can test port 3022 as an alternate port if you suspect possible firewall issues. In many cases, simply using the alternate port will get your corporate firewall to let the connection through.

Timeout

If supported in your app, please increase the connection timeout value to 60 seconds.

Retry Logic

If supported in your app, have your app attempt 3 connection retries at 10 second intervals. This allows failed connections contacting one server to retry the connection via a different server. Our hostnames always resolve to multiple physical server hosts in different datacenter locations. Ensure that your SFTP app tries multiple IPs when available.

Keepalives

Files.com will time out SFTP sessions that have been idle for 60 seconds. This is to prevent unused sessions from being left open and using server resources. Such idle timeouts are normal, and most SFTP apps handle them without issue, but there are some apps that may not handle these timeouts gracefully. To prevent these idle timeouts, many apps offer a "keepalive" setting. Many SFTP apps will complete transfers in progress and then will connect again upon the user issuing another command. If your app aborts a transfer or errors out due to the idle timeout message, you can implement keepalives (either null packets or dummy commands) every 30 seconds to maintain the SFTP connection and avoid the timeout messages.

Ciphers

Your SFTP app and Files.com will only connect if both sides agree to use a secure cipher. Insecure ciphers can be rejected by either side. Make sure that your SFTP app uses a supported secure cipher. Please check the documentation for your SFTP app to find out how to configure ciphers for your connection.