Day 11 SAMBA NFS Logs Managing Users

SAMBA Implements the ability for a Linux machine to communicate with and act like a Windows file server. –Implements File sharing Printer sharing On Linux you run smbd. Configure the smb.conf file. In windows, your linux machine appears as a new machine in the Neighborhood Network.

SAMBA For more information about SAMBA, or to find out how to install/configure it. –

nfs What if you have 2 UNIX machines who would like to share files with each other. One is a server, the other is a client. –We’ll configure both.

Server - /etc/exports Edit the file /etc/exports. Put the following in it: /usr(ro)

Server – Start services As root type: rpc.mountd rpc.nfsd To have these start automatically put them in startup files. If you make any changes to the /etc/exports file, you will need to run exportfs

Client - /etc/fstab Find out the IP address of your cousin. Make a new directory: mkdir /cousin Add the following to /etc/fstab :/usr /cousin nfs Now save that file and then type: mount -a

Testing it out Now on your machine, you should be able to see your cousins /usr partition. As setup, this is a read only mount. To change this, you would use rw instead of ro in the /etc/exports file.

User accounts One big job of a system administrator is managing users. –Adding new users when employees are hired. –Deleting old ones are they are fired/quit. –Managing user groups –Resetting passwords

Create a new user. Usually done with the adduser command. –This simply does the following: Adds a new line in /etc/passwd Creates a new directory for this person. Puts the default files into the new directory. Changes ownership and permissions of the files for the user.

Groups User groups are defined in /etc/group prof:x:101:chastine,delgado,booth,coleman,wilson,t omas,preston,enda Users can be members of multiple groups To see what groups you are a member of use: –id

Changing passwords Users can change their password at any time. –passwd Asks for old password, and then new password twice. If a user forgets their password, there is no way to find it out. –Root user can run passwd enda This will allow him to set a new password for enda, without knowing the old one.

Setting up directory. /etc/skel This is a skeleton directory which has the basic files which a user would need. –.bash_profile etc. To manually setup a user: –mkdir /home/enda –cp –R /etc/skel /home/enda –chown –R enda:enda /home/enda –chmod –R 744 /home/enda

Disable a user Usually done by either: –Change their shell to /bin/false –Or delete them from /etc/passwd –You can also user userdel enda

Logging A log file is a great resource for finding out what is going on. –Main logfile is located in /var/log /var/log/messages –Additional logs may exist in there for various applications: Web Server logs FTP Server logs Mail logs

syslogd Runs all the time in the background as a deamon. Reads configuration file /etc/syslog.conf –This determines how various levels of errors or messages are handled. Broken up as follows: –kern.*/dev/console –daemon.warning/var/log/messages These would mean: –Any message from the kernel should be written to console –Warning messages from daemons should be written to /var/log/messages.

Levels of messages Debug –You probably never care Info –General startup, shutdown of program. Notice –User enda logged out etc. Warnings –Non critical problems err –Errors from the program. Crit –Critical errors which may cause the program to crash alert –Critical errors, which may effect other things emerg –Wow…the system could crash because of this.

Who can log Messages usually come from: –daemon –kern –auth –cron –mail –local0-7 –Actual program names.

After changes - HUP Once you make changes to syslog.conf. You must tell syslogd to reread its configuration file. –kill –HUP [process ID of syslogd]

logger If you want to log something in the log file, you can use logger. –Useful in a script which may be run in background as daemon, or as a cron job. logger Test –If you want it to log under a certain priority: logger –p daemon.info “Started up”

logrotate The program logrotate can be used to rotate your logfiles. –By default on a RedHat system, logfiles are rotated every week, and the previous 4 are kept. With this weeks logfile, you have approx 5 weeks of logfiles. –Configured in: /etc/logrotate.conf If you have a very busy system, this may be too much. Nothing magical, crontab which does: –mv messages messages.old –touch /var/log/messages –kill –HUP syslogd