%general-entities; ]> $LastChangedBy$ $Date$ OpenSSH The OpenSSH package contains ssh clients and the sshd daemon. This is useful for encrypting authentication and subsequent traffic over a network. The ssh and scp commands are secure implementations of telnet and rcp respectively. &lfs10_checked; Package Information Download (HTTP): Download (FTP): Download MD5 sum: &openssh-md5sum; Download size: &openssh-size; Estimated disk space required: &openssh-buildsize; Estimated build time: &openssh-time; OpenSSH Dependencies Optional (for tests), , , , libedit, LibreSSL Portable, OpenSC, and libsectok Optional Runtime (Used only to gather entropy) , , and User Notes: OpenSSH runs as two processes when connecting to other computers. The first process is a privileged process and controls the issuance of privileges as necessary. The second process communicates with the network. Additional installation steps are necessary to set up the proper environment, which are performed by issuing the following commands as the root user: install -v -m700 -d /var/lib/sshd && chown -v root:sys /var/lib/sshd && groupadd -g 50 sshd && useradd -c 'sshd PrivSep' \ -d /var/lib/sshd \ -g sshd \ -s /bin/false \ -u 50 sshd Install OpenSSH by running the following commands: ./configure --prefix=/usr \ --sysconfdir=/etc/ssh \ --with-md5-passwords \ --with-privsep-path=/var/lib/sshd && make The testsuite requires an installed copy of scp to complete the multiplexing tests. To run the test suite, first copy the scp program to /usr/bin, making sure that you backup any existing copy first. To test the results, issue: make -j1 tests. Now, as the root user: make install && install -v -m755 contrib/ssh-copy-id /usr/bin && install -v -m644 contrib/ssh-copy-id.1 \ /usr/share/man/man1 && install -v -m755 -d /usr/share/doc/openssh-&openssh-version; && install -v -m644 INSTALL LICENCE OVERVIEW README* \ /usr/share/doc/openssh-&openssh-version; --sysconfdir=/etc/ssh: This prevents the configuration files from being installed in /usr/etc. --with-md5-passwords: This enables the use of MD5 passwords. --with-pam: This parameter enables Linux-PAM support in the build. --with-xauth=/usr/bin/xauth: Set the default location for the xauth binary for X authentication. Change the location if xauth will be installed to a different path. This can also be controlled from sshd_config with the XAuthLocation keyword. You can omit this switch if Xorg is already installed. --with-kerberos5=/usr: This option is used to include Kerberos 5 support in the build. --with-libedit: This option enables line editing and history features for sftp. ~/.ssh/*, /etc/ssh/ssh_config, and /etc/ssh/sshd_config ~/.ssh/* /etc/ssh/ssh_config /etc/ssh/sshd_config There are no required changes to any of these files. However, you may wish to view the /etc/ssh/ files and make any changes appropriate for the security of your system. One recommended change is that you disable root login via ssh. Execute the following command as the root user to disable root login via ssh: echo "PermitRootLogin no" >> /etc/ssh/sshd_config If you want to be able to log in without typing in your password, first create ~/.ssh/id_rsa and ~/.ssh/id_rsa.pub with ssh-keygen and then copy ~/.ssh/id_rsa.pub to ~/.ssh/authorized_keys on the remote computer that you want to log into. You'll need to change REMOTE_USERNAME and REMOTE_HOSTNAME for the username and hostname of the remote computer and you'll also need to enter your password for the ssh-copy-id command to succeed: ssh-keygen && ssh-copy-id -i ~/.ssh/id_rsa.pub REMOTE_USERNAME@REMOTE_HOSTNAME Once you've got passwordless logins working it's actually more secure than logging in with a password (as the private key is much longer than most people's passwords). If you would like to now disable password logins, as the root user: echo "PasswordAuthentication no" >> /etc/ssh/sshd_config && echo "ChallengeResponseAuthentication no" >> /etc/ssh/sshd_config If you added Linux-PAM support and you want ssh to use it then you will need to add a configuration file for sshd and enable use of LinuxPAM. Note, ssh only uses PAM to check passwords, if you've disabled password logins these commands are not needed. If you want to use PAM, issue the following commands as the root user: sed 's@d/login@d/sshd@g' /etc/pam.d/login > /etc/pam.d/sshd && chmod 644 /etc/pam.d/sshd && echo "UsePAM yes" >> /etc/ssh/sshd_config Additional configuration information can be found in the man pages for sshd, ssh and ssh-agent. To start the SSH server at system boot, install the /etc/rc.d/init.d/sshd init script included in the package. To start the SSH server at system boot, install the sshd.service unit included in the package. sshd make install-sshd Installed Programs Installed Libraries Installed Directories scp, sftp, slogin (symlink to ssh), ssh, ssh-add, ssh-agent, ssh-copy-id, ssh-keygen, ssh-keyscan, and sshd None /etc/ssh, /usr/share/doc/openssh-&openssh-version;, and /var/lib/sshd Short Descriptions scp is a file copy program that acts like rcp except it uses an encrypted protocol. scp sftp is an FTP-like program that works over the SSH1 and SSH2 protocols. sftp slogin is a symlink to ssh. slogin ssh is an rlogin/rsh-like client program except it uses an encrypted protocol. ssh sshd is a daemon that listens for ssh login requests. sshd ssh-add is a tool which adds keys to the ssh-agent. ssh-add ssh-agent is an authentication agent that can store private keys. ssh-agent ssh-copy-id is a script that enables logins on remote machine using local keys. ssh-copy-id ssh-keygen is a key generation tool. ssh-keygen ssh-keyscan is a utility for gathering public host keys from a number of hosts. ssh-keyscan