Opensshserver yum y install opensshserver opensshclients yum y install opensshclients.Configure Vsftpd ftp server to use SSLTLS encryption on Ubuntu and CentOS based Linux systems.Habilitar acceso remoto mediante SSH en Linux CentOS con OpenSSH Proyecto AjpdSoft.The one I will discuss in this article is SSH, a secure remote protocol which is used to work remotely on other machines or transfer data between computers.Uhp92PNeQY/hqdefault.jpg' alt='How To Install Openssh On Centos 5' title='How To Install Openssh On Centos 5' />Cent.OS 5 SSHSFTP for remote access and secure file transfers Open.SSH Cent. OS 5 How to guide.This how to will show you how to configure Remote access over SSH via Open.SSHSecure, password less authentication.Optional Open. SSH 5.Secure file transfers over SFTPConfiguring Open.SSHopenssh server is already installed by default, it just needs to be configured.We will disable root logins as well as all password based logins in favour of the more secure public key authentication.If you do not already have a SSH key, you should take the time to create one now by running ssh keygen on the computer you will be using to access the server remotely.The following will configure SSH as described above cat lt lt EOF etcsshsshdconfig Customizations Some of the settings here duplicate defaults, however this is to ensure that if for some reason the defaults change in the future, your servers configuration will not be affected.Do not allow root to login over SSH. Naruto Shippuden Episode 165 English Subbed Download Youtube . If you need to become root, login as your regular use and use su instead.Permit. Root. Login no Disable password authentication and enable key authentication.This will force users to use key based authentication which is more secure and will protect against some automated brute force attacks on the server.As well, this section disables some unneeded authentication types.If you wish to use them, modify this section accordingly.Password. Authentication no.Pubkey. Authentication yes.Challenge. Response.Authentication no.Kerberos. Authentication no Do not allow TCP or X1.Allow. Tcp. Forwarding no.X1. 1Forwarding no Why give such a large window If the user has not provided credentials in 3.Login. Grace. Time 3.EOFLets make sure SSH starts on boot, restart the service immediately and finally add the firewall exception for port 2.I RH Firewall 1 INPUT 4 m state state NEW m tcp p tcp dport 2.ACCEPTservice iptables save.Because we have disabled root access over SSH, it is time to create a regular user that you can used to login over ssh and then gain root access useradd myusernamepasswd myusernamesu myusernamemkdir m 0.Now add the contents of your.Optional but recommended Rebuilding Open.SSH 5. x. Although SSH will function perfectly fine with this bare configuration, it is not the most secure possible.Cent. OS 5 comes with Open.SSH version 4. 3p.Instead of using 4.Open. SSH version 5.Fedora 1. 3 can be rebuilt which offers a slew of new features such as access control via usergroup matching and SFTP jailrooting.Before the package can be rebuilt, a few changes need to be made to make it work on Cent.OS 5. Edit opensshF 1.Build. Requires tcpwrappers devel at approximately line number 1.Simply remove the devel so that the line now reads Build.Requires tcpwrappers.Just below, you will also notice a statement Build.Requires openssl devel 0.Remove the version requirement so that the line reads Build.Requires openssl devel.Lastly, near line 1.Requires pam 1. Requires pam.Now that the RPM spec file has been modified, we also need to change the PAM configuration file as the one from Fedora 1.Cent. OS 5 cat lt lt EOF sshd.PAM 1. 0auth include system authaccount required pamnologin.EOFThe package is ready to be rebuild for Cent.OS 5. Execute the following to rebuild and install Open.SSH 5. 4p. 1 yum install gtk.X1. 1 devel autoconf automake zlib devel audit libs devel pam devel fipscheck devel openssl devel krb.Uhv homemyusernamerebuildsopenssharchopenssh 5,server,clients.Remember to replace arch in the second to last command with the appropriate value most probably i.We can take now advantage of the new features to harden SSH The configuration segment below will restrict access for members of the servsftponly group such that only SFTP access is permitted and those users are jailed to the web folder in their home directory so that they can only uploaddownload files from their website.Members of the servsshall group have full SSH and SFTP access, as well as X1.TCP forwarding. mkdir srvsftpgroupadd servsftponlygroupadd servsshallusermod a G servsshall myusernamesed i sSubsystemtsftptusrlibexecopensshsftp serverSubsystemtsftptusrlibexecopensshsftp server etcsshsshdconfigcat lt lt EOF etcsshsshdconfig Access control We need to use the internal sftp subsystem.Subsystem sftp internal sftp Allow access if user is in these groups.Allow. Groups servsftponly servsshall We cant use a path relative to or h because we make the user homes publichtml in order to get the chroot above working properly.As a result, we need to set an absolute path that will make SSH look in the usual place for authorized keys.Authorized. Keys.File homeu. sshauthorizedkeys Give tunnelling X1.Match group servsshall.X1. 1Forwarding yes.Allow. Tcp. Forwarding yes Restrict users who are members of group servsftponlyMatch group servsftponly Some settings here may duplicate the global settings, just to be safe.Password. Authentication yes.X1. 1Forwarding no.Allow. Tcp. Forwarding no Force the internal SFTP subsystem and jailroot the user in their home.Force. Command internal sftp.Chroot. Directory srvsftpu.EOFservice sshd restart.The srvsftpusername folder is used instead of the users entire home because it prevents the user from making any potentially unwanted configuration changes such as authorizing additional ssh public keys as well as accidentally deleting files, such as the mail folder which holds all of that domains emails.One now simply needs to link srvsftpusername to the appropriate web folder to jail the user there.For example ln s.You do not need to do this manually, as the user setup script will run this for you.As well, note that the configuration includes the commented line Password.Authentication Yes in the servsftponly Match.Group section. If you so wish, you can uncomment this line to have password authentication enabled ONLY for users of the servsftponly group.While password authentication is less secure than public key authentication, it is much more convenient for your clients if you are building a shared hosting machine and if a hacker does gain access because a user had an easy to guess password, they only gain access to a single jailed SFTP client.Denyhosts. You may be wondering why I havent included any information about software that can block repeated SSH intrusions such as denyhosts.I have placed this information, along with other server security tips, in the security tutorial coming soon.Please see it for more information.Administering the server.Setting up the scripts.The following code will setup the hostinguseradd script which can be used to add new hosting users on your server mkdir p rootbincat lt lt EOF rootbinhostinguseraddbinsh chown root.Usage 1 user. 1 user.Restrict username make member of servsftponly Yn t 6.N thenecho Creating normal user usernameuseradd G servsshall usernameelseecho Creating restricted user usernameuseradd G servsftponly s sbinnologin usernamefichown username.Set passwordpasswd username Initialize mail storage foldermkdir m 0.Initialize web foldersmkdir p m 0.Web logsmkdir p m 0.Web offlineprivate storagemkdir p m 0.Web docrootmkdir m 0.Web PHP error logtouch homeusernamewebphperrorlogchown username.Initialize session foldermkdir m 0.SSH SFTP loginln s.SSH Authorized keys dirmkdir m 0.Key description hereecho yourkeyhere homeusername.EOFchmod x rootbinhostinguseradd.You will need to edit rootbinhostinguseradd later and replace yourkeyhere with your own SSH key so that you can login to the account should you ever need to test or do administration work.Adding a new system accountrootbinhostinguseradd newusername.If you are adding many accounts, you can optionally specify more than one username to have each account be created at once.
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