Chilkat SSH – SendReqExec vs SendReqShell

Chilkat’s SSH class provides the ability to start a shell session by calling SendReqShell, or by calling QuickShell.  You can alternatively run a single remote command by calling SendReqExec. SendReqExec does the “exec” command, whereas SendReqShell (or QuickShell) starts an interactive shell session where bytes sent to the SSH server via methods such as ChannelSendString are the equivalent of keystrokes […]

Chilkat v9.5.0.97 Mitigates Vulnerability to the SSH Terrapin Attack

Chilkat v9.5.0.97 makes changes to mitigate the Terrapin attack problem. It does so by modifying the selection of the default algorithms in the following ways: chacha20-poly1305@openssh.com is no longer included by default. It can be re-added by specifying “+chacha20-poly1305@openssh.com” in the UncommonOptions property. We are going to keep the “-cbc” encryption modes because potentially too many servers would be affected […]

Chilkat 5-Jan-2022 Remote SSH Commands on Cisco and Dell Force 10 Switches

What’s going on w/ Chilkat today… 1. User trying to execute remote SSH commands on two different switches:  One is a Cisco switch, the second is a Dell Force 10.   All working fine w/ Ssh.QuickCommand on the Cisco switch, but not the Dell Force 10.   The QuickCommand method as shown in the example at https://www.example-code.com/vbnet/ssh_execute_remote_commands.asp  is the equivalent of doing […]

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 […]