network protocols handbook.pdf

32Protocols GuideTCP/IP - Application Layer ProtocolsProtocol Namerlogin: Remote Login in UNIXSystemsProtocol Descriptionrlogin (remote login) is a UNIX command that allows an authorizeduser to login to other UNIX machines (hosts) on a networkand to interact as if the user were physically at the host computer.Once logged in to the host, the user can do anything thatthe host has given permission for, such as read, edit, or deletefiles.Each remote machine may have a file named /etc/hosts.equivcontaining a list of trusted hostnames with which it shares usernames.Users with the same username on both the local and remotemachine may rlogin from the machines listed in the remotemachine’s /etc/hosts.equiv file without supplying a password.Individual users may set up a similar private equivalence listwith the file .rhosts in their home directories. Each line in this filecontains two names: a host name and a username separated bya space. An entry in a remote user’s .rhosts file permits the usernamed username who is logged into hostname to log in to theremote machine as the remote user without supplying a password.If the name of the local host is not found in the /etc/hosts.equiv file on the remote machine and the local username andhostname are not found in the remote user’s .rhosts file, thenthe remote machine will prompt for a password. Hostnameslisted in /etc/hosts.equiv and .rhosts files must be the officialhostnames listed in the host’s database; nicknames may not beused in either of these files. For security reasons, the .rhosts filemust be owned by either the remote user or by root.The remote terminal type is the same as your local terminal type(as given in your environment TERM variable). The terminal orwindow size is also copied to the remote system if the serversupports the option, and changes in size are reflected as well.All echoing takes place at the remote site, so that (except for delays)the remote login is transparent. Flow control using and and flushing of input and output on interruptsare handled properly.A secure version of rlogin (slogin) was combined with two otherUNIX utilities, ssh and scp, in the Secure Shell suite, an interfaceand protocol created to replace the earlier utilities.-8EL-e Character-f-F-k realm-l UserHostnameRelated protocolsFTP, TELNETSponsor Sourcerlogin is a UNIX command.Allows an 8-bit data path at all times. Otherwise, unlessthe start and stop characters on the remote hostare not Ctrl-S and Ctrl-Q, the rlogin command uses a7-bit data path and parity bits are stripped.Changes the escape character. Substitute the characteryou choose for Character.Causes the credentials to be forwarded. This flag willbe ignored if Kerberos 5 is not the current authenticationmethod. Authentication will fail if the current DCEcredentials are not marked forwardable.Causes the credentials to be forwarded. In addition,the credentials on the remote system will be markedforwardable (allowing them to be passed to anotherremote system). This flag will be ignored if Kerberos5 is not the current authentication method. Authenticationwill fail if the current DCE credentials are notmarked forwardable.Allows the user to specify the realm of the remote stationif it is different from the local systems realm. Forthese purposes, a realm is synonymous with a DCEcell. This flag will be ignored if Kerberos 5 is not thecurrent authentication method.Changes the remote user name to the one you specify.Otherwise, your local user name is used at the remotehost.The remote machine on which rlogin establishesthe remote login session.Referencehttp://www.javvin.com/protocol/rfc1282.pdfBSD RloginProtocol Structurerlogin command is:rlogin [-8EL] [-ec ] [-l username] hostnameOPTION Flags