A shell account is a user account on a remote server, typically running under Unix or Linux operating systems. The account gives access to a text-based command-line interface in a shell, via a terminal emulator. The user typically communicates with the server via the SSH protocol. In the early days of the Internet, one would connect using a modem.
Shell accounts were first made accessible in the 1980's to interested members of the public by Internet Service Providers—such as Netcom, Panix, The World, Digex—although in rare instances individuals had access to shell accounts through their employer or university. They were used for file storage, web space, email accounts, newsgroup access and software development. [1] [2] [3] Before the late 1990s, shell accounts were often much less expensive than full net access through SLIP or PPP, which was required to access the then-new World Wide Web. Most personal computer operating systems also lacked TCP/IP stacks by default before the mid-1990s. Products such as The Internet Adapter were devised that could work as a proxy server, allowing users to run a web browser for the price of a shell account. [4]
While direct internet connections made shell accounts largely obsolete for most users, they remained popular with some technically inclined subscribers. [5]
Shell providers are often found to offer shell accounts at low-cost or free. These shell accounts generally provide users with access to various software and services including compilers, IRC clients, background processes, FTP, text editors (such as nano) and email clients (such as pine). [6] Some shell providers may also allow tunneling of traffic to bypass corporate firewalls.
The Secure Shell Protocol (SSH) is a cryptographic network protocol for operating network services securely over an unsecured network. Its most notable applications are remote login and command-line execution.
Telnet is a client/server application protocol that provides access to virtual terminals of remote systems on local area networks or the Internet. It is a protocol for bidirectional 8-bit communications. Its main goal was to connect terminal devices and terminal-oriented processes.
An email client, email reader or, more formally, message user agent (MUA) or mail user agent is a computer program used to access and manage a user's email.
A terminal emulator, or terminal application, is a computer program that emulates a video terminal within some other display architecture. Though typically synonymous with a shell or text terminal, the term terminal covers all remote terminals, including graphical interfaces. A terminal emulator inside a graphical user interface is often called a terminal window.
UUCP is a suite of computer programs and protocols allowing remote execution of commands and transfer of files, email and netnews between computers.
Unix security refers to the means of securing a Unix or Unix-like operating system. A secure environment is achieved not only by the design concepts of these operating systems, but also through vigilant user and administrative practices.
SOCKS is an Internet protocol that exchanges network packets between a client and server through a proxy server. SOCKS5 optionally provides authentication so only authorized users may access a server. Practically, a SOCKS server proxies TCP connections to an arbitrary IP address, and provides a means for UDP packets to be forwarded. A SOCKS server accepts incoming client connection on TCP port 1080, as defined in RFC 1928.
An online service provider (OSP) can, for example, be an Internet service provider, an email provider, a news provider (press), an entertainment provider, a search engine, an e-commerce site, an online banking site, a health site, an official government site, social media, a wiki, or a Usenet newsgroup.
The Berkeley r-commands are a suite of computer programs designed to enable users of one Unix system to log in or issue commands to another Unix computer via TCP/IP computer network. The r-commands were developed in 1982 by the Computer Systems Research Group at the University of California, Berkeley, based on an early implementation of TCP/IP.
In computer networking, port forwarding or port mapping is an application of network address translation (NAT) that redirects a communication request from one address and port number combination to another while the packets are traversing a network gateway, such as a router or firewall. This technique is most commonly used to make services on a host residing on a protected or masqueraded (internal) network available to hosts on the opposite side of the gateway, by remapping the destination IP address and port number of the communication to an internal host.
A remote access service (RAS) is any combination of hardware and software to enable the remote access tools or information that typically reside on a network of IT devices.
In computer networks, a tunneling protocol is a communication protocol which allows for the movement of data from one network to another. It can, for example, allow private network communications to be sent across a public network, or for one network protocol to be carried over an incompatible network, through a process called encapsulation.
SlipKnot was one of the earliest World Wide Web browsers, available to Microsoft Windows users between November 1994 and January 1998. It was created by Peter Brooks of MicroMind, Inc. to provide a fully graphical view of the web for users without a SLIP or other TCP/IP connection to the net, hence the name – SLIP...not. SlipKnot provided a graphical web experience through what would otherwise be a text-only Unix shell account. SlipKnot version 1.0 was released on November 22, 1994, approximately 3 weeks before Netscape's Netscape Navigator version 1.0 came out. It was designed to serve a significant fraction of PC/Windows-based Internet users who could not use Mosaic or Netscape at that time.
A terminal server connects devices with a serial port to a local area network (LAN). Products marketed as terminal servers can be very simple devices that do not offer any security functionality, such as data encryption and user authentication. The primary application scenario is to enable serial devices to access network server applications, or vice versa, where security of the data on the LAN is not generally an issue. There are also many terminal servers on the market that have highly advanced security functionality to ensure that only qualified personnel can access various servers and that any data that is transmitted across the LAN, or over the Internet, is encrypted. Usually, companies that need a terminal server with these advanced functions want to remotely control, monitor, diagnose and troubleshoot equipment over a telecommunications network.
In computing, a shell is a computer program that exposes an operating system's services to a human user or other programs. In general, operating system shells use either a command-line interface (CLI) or graphical user interface (GUI), depending on a computer's role and particular operation. It is named a shell because it is the outermost layer around the operating system.
Internet fax, e-fax, or online fax is the use of the internet and internet protocols to send a fax (facsimile), rather than using a standard telephone connection and a fax machine. A distinguishing feature of Internet fax, compared to other Internet communications such as email, is the ability to exchange fax messages with traditional telephone-based fax machines.
The Internet Adapter (TIA) was software created by Cyberspace Development in 1993 to allow Serial Line Internet Protocol (SLIP) connections over a shell account. Point-to-Point Protocol (PPP) was added in 1995, by which time the software was marketed and sold by Intermind of Seattle. Shell accounts normally only allow the use of command line or text-based software, but by logging into a shell account and starting the TIA daemon, a user could then run any TCP/IP-based application, including standard GUI software such as the then-popular Netscape Navigator on their computer. This was especially useful at the time because simple shell accounts were much less expensive than full SLIP/PPP accounts. TIA was ported to a large number of unix or unix-like systems.
Slirp is a software program that emulates a PPP, SLIP, or CSLIP connection to the Internet using a text-based shell account. Its original purpose became largely obsolete as dedicated dial-up PPP connections and broadband Internet access became widely available and inexpensive. It then found additional use in connecting mobile devices, such as PDAs, via their serial ports. Another significant use case is firewall piercing/port forwarding. One typical use of Slirp creates a general purpose network connection over a SSH session on which port forwarding is restricted. Another use case is to create external network connectivity for unprivileged containers.
A headless computer is a computer system or device that has been configured to operate without a monitor, keyboard, and mouse. A headless system is typically controlled over a network connection, although some headless system devices require a serial connection to be made over RS-232 for administration of the device. Headless operation of a server is typically employed to reduce operating costs.
OpenSSH is a suite of secure networking utilities based on the Secure Shell (SSH) protocol, which provides a secure channel over an unsecured network in a client–server architecture.
If you are comfortable with the command-line interface that Linux provides, you will probably be comfortable with a Shell account on a Linux or Unix computer managed by an ISP. Once your modem connects to the other modem and you log in, it is the same as an xterm session or a console login (without graphics capabilities) on your Linux box, except that the remote computer you are logged into is connected to the Internet. You usually use a standard Unix shell, with roughly the same choices available on your own Linux system, although some shell accounts also provide an optional menu interface similar to what a BBS provides.
The other day, I started shopping, both for a Unix shell account, and for a SLIP or PPP connection that allows my home Linux network to become a real part of the Internet.
Until recently, if you wanted to use Mosaic for the World Wide Web, you needed a direct SLIP or PPP connection to the Internet. In many countries, such a connection costs a leg and an arm. Now, you can also use Mosaic if you connect to the Internet through a Unix shell account. The administrators may not even notice that you do.