![]() Note that this key may be renegotiated between the client and the server on a periodic basis by including the RekeyIntervalSeconds keyword in the server configuration file (SSH2_DIR:SSHD2_CONFIG). This key is used to encrypt all further communications in the session. The client and server together, using the Diffie-Hellman key-exchange method, determine a 256-bit random number to use as the "session key". When a client connects to the SSHD daemon: For example, each machine in a VMScluster could use the same key. The same key may be used on multiple machines. Examples of such programs are MultiNet SSH2 for OpenVMS SecureCRT®, and F-Secure SSH Client for Windows®, MacSSH for Macintosh® systems, and other SSH programs on UNIX-based systems.Įach host has a key using DSA encryption and is usually 1024 bits long (although, the user may create a different-sized key, if desired). A client program (SSH) is provided with TCPware, but any SSH client that uses SSH version 2 protocol may be used to access the server. SSHD handles all the interaction with the SSH client.Ī client is any system that accesses the server. SSHD, a copy of which is spawned for each connection instance. If the request is for SSH v1, then the existing SSH v1 server is run if the request is for SSH v2, then the SSH v2 server is run. SSHD_MASTER, recognizes the differences between SSH v1 and SSH v2 and starts the appropriate server. The server software consists of two pieces of software (for future reference, "SSHD" will refer to both SSHD_MASTER and SSHD, unless otherwise specified): ![]() These daemons handle key exchange, encryption, authentication, command execution, and data exchange.Ī TCPware SSH server is an OpenVMS system that acts as a host for executing interactive commands or for conducting an interactive session. A new daemon is created for each incoming connection. The server/client programs provide secure encrypted communications between two untrusted hosts over an insecure network. The server program replaces rshell and telnet programs. Secure Shell daemon (SSHD) is the daemon program for SSH2 that listens for connections from clients. Understanding the TCPware Secure Shell Server If this behavior poses a problem, log into the remote system using SSH2 in interactive mode to execute the program. In addition, some interactive programs such as HELP may not function as expected. When using SSH2 to execute single commands (in the same manner as RSHELL), some keystrokes like CTRL/Y are ignored. If the VMS primary password entered is valid, the user is logged in, bypassing the secondary password. When using SSH2 to connect to a VMS server, if the VMS account is set up with a secondary password, SSH2 does not prompt the user for the secondary password. You can find the ECO on the TCPware CD in the following directory: VAX55_DECC_RTL.DIR. Note! You must install the DEC C 6.0 backport library on all OpenVMS VAX v6.0 and earlier systems prior to using SSH. The cryptographic library used by TCPware SSH2 ( this does not apply to SSH1 sessions) is compiled from unaltered cryptographic source code from F-Secure which is FIPS 140-2 level 2 compliant, as determined by the Computer Security Division of the National Institute of Science and Technology (NIST). The TCPware server front-end identifies what protocol a client desires to use, and will create an appropriate server for that client While SSH2 is generally regarded to be more secure than SSH1, both protocols are offered by TCPware, and although they are incompatible, they may exist simultaneously on a TCPware system. The TCPware SSH1 implementation is based on the version 1.3.7 protocol, and the TCPware SSH2 implementation is based on the WRQ RSIT 6.1.0 code base. SSH1 and SSH2 are different, and incompatible, protocols. The SSH server has been developed to discriminate between SSH v1 and SSH v2 protocols, so the two protocols can coexist simultaneously on the same system. This is the server side of the software that allows secure interactive connections to other computers in the manner of rlogin/rshell/telnet. This chapter describes how to configure and maintain the TCPware Secure Shell (SSH) server v2.
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