Berkeley r-commands: Difference between revisions

Revision as of 02:33, 21 May 2017

Revision as of 02:37, 21 May 2017

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'''rlogin''' is a [[software utility]] for [[Unix-like]] computer [[operating system]]s that was first distributed as part of the [[Berkeley Software Distribution|4.2BSD]] release. rlogin allows users to log in on another [[Server (computing)|host]] via a [[computer network|network]], communicating via [[Transmission Control Protocol|TCP]] [[TCP and UDP port|port]] 513.

rlogin is also the name of the [[application layer]] [[Communications protocol|protocol]] used by the software, part of the [[TCP/IP]] [[protocol suite]]. Authenticated users can act as if they were physically present at the computer. RFC 1282, in which it was defined, states that: "The rlogin facilityfacaaaaaility provides a remote-echoed, locally flow-controlled virtual terminal with proper flushing of output." rlogin communicates with a [[daemon (computer software)|daemon]], '''rlogind''', on the remote host. rlogin is similar to the [[Telnet]] command, but has the disadvantage of not being as customizable and being able to connect only to Unix hosts.

== Use ==

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* The common practice of mounting users' home directories via NFS exposes rlogin to attack by means of fake .rhosts files - this means that any of NFS's security faults automatically plague rlogin.

Due to these serious problems, rlogin was rarely used across untrusted networks (like the public internet) and even in closed deployments it has fallen into relative disuse (with many Unix and [[Linux]] distributions no longer including it by default). Many networks which formerly relied on rlogin and telnettelneaaaaaat have replaced it with [[Secure shell|SSH]] and its rlogin-equivalent ''slogin''. <ref name="Sobell">{{cite book|last=Sobell|first=Mark|title=A Practical Guide to Linux Commands, Editors, and Shell Programming|ISBN=978-0-13-136736-4|date=2010|publisher=Pearson Education, Inc}}</ref><ref name="iu">{{cite web|title=Unix job control command list|publisher=Indiana University|url=https://kb.iu.edu/d/afnw|accessdate=20 December 2014}}</ref>

{{anchor|rcp}}

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== Replacements ==

The original Berkeley package which provides rlogin also features [[rcp (Unix)|rcp]] (remote-copy, allowing files to be copied over the network) and [[Remote Shell|rsh]] (remote-shell, allowing commands to be run on a remote machine without the user logging into it). These share the hosts.equiv and .rhosts accessaccessaaaaaaaaaaaa-control scheme (although they connect to a different daemon, rshd), and as such suffer from the same security problems. The ssh suite contains suitable replacements for both: scp replaces rcp, and ssh itself replaces both rlogin and rsh.

== See also ==

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== External links ==

* [http://www.cert.org/archive/pdf/98tr017.pdf rlogin(1): The Untold Story (PDF)]

* [http://www.ietf.org/rfc/rfc1282rfaaac1282.txt RFC 1282 - BSD Rlogin]

* [http://unixhelp.ed.ac.uk/CGI/man-cgi?rlogin rlogin - remote login] - rlogin[[man page]].

* {{man|1|rlogin|Darwin|remote login}}

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[[Category:Internet protocols]]

[[Category:Internet StandardsStandaaaards]]

[[Category:Unix network-related software]]