Downloading Super-Huge Files via FTP, SFTP, Http, etc.

It seems that more and more nowadays, Chilkat has customers needing to download gigantic files (many Gigabytes) using various protocols such as SFTP, FTP, or HTTP. These downloads can take a long time, even with a very good transfer rate. The longer the download time, the higher the probability that something goes wrong: network congestion, connectivity issues, server problems, etc. […]

SSH Authentication Options in sshd_config

The /etc/ssh/sshd_config file has an entry called AuthenticationMethods. Typically you would enter either: to indicate which authentication method should be required. You can also enter: to indicate that either authentication method should be required. You can also enter: to indicate that both authentication methods should be required. If a server requires both publickey and password, then call AuthenticatePwPk. If a […]

Understanding Chilkat’s SSH Tunnel Class

Before Chilkat’s SSH Tunnel, your app would need to connect to a tunnel process/service running either on the local machine or on some computer on the LAN, and then tunnel out to the remote server.  It would look like this: App ——(1)——>  TunnelService —-(2)——> SshServer —-(3)—–> SomeDestServerSuchAsSQL You can wrap a non-encrypted TCP connection, or a TLS connection within the […]

Multi-Hop SSH Tunneling for Chilkat v9.5.0.55

The ability to multi-hop SSH tunnels is available for testing in the Chilkat v9.5.0.55 pre-release. The typical schemes for multiple hop SSH look like this: (for running a remote shell or commands on SSH_server_B) application => SSH_server_A => SSH_server_B (for connecting to a remote host:port, via Socket with TCP or TLS) application(TCP_or_TLS) => SSH_server_A => SSH_server_B => destHost:destPort (IMAP) application […]

SFTP vs. FTPS

Clarification on the acronyms “SFTP” and “FTPS” “SFTP” is the Secure File Transfer Protocol over SSH.  It is a protocol unrelated to the FTP protocol. (It is actually a subsystem of SSH.)  The Chilkat SSH / SFTP component is used for “SFTP”.  SFTP is achieved by connecting to an SSH server at port 22. On the other hand, the Chilkat […]

SSH SendReqExec — Interactive Commands such as “more”

Commands that assume an interactive user at a shell prompt should not be passed to SendRequestExec.  For example, the “more” command assumes there is a shell and that the user will press RETURN when another screenful of text is wanted.  It would be more appropriate to use the Unix/Linux “cat” command w/ SendRequestExec. To run interactive commands, one should instead […]