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Building Embedded Linux Systems by Karim Yaghmour

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Network Login Through Telnet

The Telnet protocol is one of the simplest ways to log in to a remote network host. Consequently, it's the easiest way to access your target system once it is connected to a network. To enable remote login, your target must run a Telnet daemon. There are two main Telnet daemons available for use in embedded Linux systems, telnetd, which is part of the netkit packages mentioned earlier, and utelnetd, which is maintained by Robert Schwebel of Pengutronix. In terms of size, the binary generated by the utelnetd package is clearly smaller than the one generated by the netkit Telnet package. In addition, utelnetd does not require an internet super-server, while telnetd does. If your system has very limited resources and does not include other network services managed by an internet super-server, use utelnetd.

Though Telnet is a convenient, lightweight communications mechanism for managing your device on a dedicated network, it's not a secure protocol and is, therefore, not fit for use on the Internet. If you need to remotely log in a device that resides on the Internet, use SSH instead. We will discuss SSH in detail in Section 10.4.

netkit-telnetd

As with other netkit packages, netkit-telnet, which contains telnetd, is distributed at ftp://ftp.uk.linux.org/pub/linux/Networking/netkit/ under a BSD license. For my SYSM module, I used netkit-telnet Version 0.17.

Download and extract the netkit-telnet package into your ${PRJROOT}/sysapps directory and move ...

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