Red hat enterprise linux 7 boot process

CCIE 12932: Unity Connection-CUCME Lab 3 – Unity ...

An operating system’s filesystem structure is its most basic level of organization. 1 Why Share a Common Structure. 2:Overview of Filesystem Hierarchy Standard (FHS) 1 Filesystem Structure 1. Almost all of the ways an operating system interacts with its users, applications, and security model are dependent upon the way it stores its files on a primary storage device (normally a hard disk drive).

3:NFS Client Configuration Files 17. 3 NFS Client Configuration Files Any NFS share made available by a server can be mounted using various methods. Of course, the share can be manually mounted, using themount command, to acquire the exported filesystem at a particular mount point.

O ni52=io_port,IRQ OR ni52 Ethernet chip) io=io_port irq=IRQ NI6510 Ethernet ni65. O AMD PCnet32 and AMD pcnet32. O PCnetPCI SysKonnect SK-98XX sk98lin. 4:Ethernet parameters Hardware Module Parameters MiCom-Interlan NI5010 ni5010. O NI5210 card (i82586 ni52. O SMC Ultra and SMC smc-ultra=io_port,IRQ OR EtherEZ ISA ethercard smc-ultra io=io_port irq=IRQ (8K, 83c790).

# vi ftpusers
      ftp Additonal comments about access control files
The ipchains configuration file defines which IP packets are accepted, rejected, or denied by the Linux machine. Other services (telnet, ftp, rsh, rexec) are controlled by the xinetd daemon. Domain}   {hostname}   localhost. , the system is intended to be a mail server from which you will regularly read mail. Allow
# cd /etc/sysconfig
# vi ipchains
      -A input -s 0/0 -d 0/0 110 -p tcp -y -j ACCEPT
      -A input -s 0/0 -d 0/0 110 -p udp -j ACCEPT
# /sbin/service ipchains restart Remove anonymous ftp access
Most servers prefer not provide anonymous ftp service, which would permit anyone to download files from the /var/ftp/pub directory without providing a password. Rpm Install and setup computational chemistry software Setup scratch directory
# cd /scratch
# rm -r lost+found
# chmod 777 /scratch
# chmod +t /scratch Install computational chemistry engines Pre-compiled binaries save the time and trouble of downloading and compiling program source code. (Note that the Powertools CDROM is no longer produced as of Red Hat Linux 7. However, telnet is sometimes used on a secure local network when security is less of a concern. By default, Red Hat Linux 7. Rpm
# rpm -Uvh kernel-headers-{new_version}. Many services have both client and server rpm’s, and it is the server package that must be present. Deny contains no entries or /etc/hosts. To turn on telnet
# cd /etc/xinet. By default, directories are created with mode 775 in Red Hat Linux. Xxx (Fills in automatically) Broadcast: xxx. Thus, it is generally best to allow access to specific services by certain address in hosts. However, passwords for these shares are maintained separately from the Linux login passwords. Boot Loader Installation Use GRUB as the boot loader Install Boot Loader record on /dev/hda Master Boot Record (MBR) Do not enter a GRUB password unless needed Network Configuration Uncheck ‘Configure using DHCP’ Make the following settings: (talk to you network adminstrator for correct values) IP address: {ip_address} Netmask: {subnet_mask} Network: xxx. If ssh fails,make sure that the iphains firewall contains a line for service 22 (ssh) like
      -A input -s 0/0 -d 0/0 22 -p tcp -y -j ACCEPT
that the ssh server software is installed
# rpm -qa | grep openssh-server
and that either /etc/hosts. Conf | grep Indexes
For example, change
      Options MultiViews Indexes SymLinksIfOwnerMatch IncludesNoExec
      Options MultiViews SymLinksIfOwnerMatch IncludesNoExec
Make sure that the /etc/sysconfig/ipchains firewall configuration file contains a line for service 80 (http) like
      -A input -s 0/0 -d 0/0 80 -p tcp -y -j ACCEPT
Restart the firewall if ipchains was edited
# /sbin/service ipchains restart
Start the apache server
# /sbin/chkconfig httpd on
# /sbin/service httpd start
Note that suexec is turned on by default in Red Hat Linux 7. Telnet
Telnet is not generally recommended because login information (username and password) and all commands (su and root password) are transmitted as plain text. Since this is not the default installation, one must become root and do a chmod 711 on all /home/user directories
# cd /home
# chmod 711 {user}
Each user must then create a public_html directory structure
$ cd ~
$ mkdir public_html
$ cd public_html
$ mkdir cgi-bin
$ chmod 755 cgi-bin
Edit the apache configuration file
# cd /etc/httpd/conf
# cp -p httpd. These may be turned on by editing the appropriate file in /etc/xinet. Instructions and pre-compiled binaries are available for the Linux operating system MOPAC
MOPAC 7 pre-compiled binary for Linux
GAMESS pre-compiled binary for Linux Compiling the source code allows software to be installed on a wider array of hardware and oparting systems MOPAC
MOPAC 7 installation instructions for Linux
MOPAC 2000 installation instructions for Linux
GAMESS installation instructions for Linux
Gaussian 94 installation instructions for Linux
Portland Group F77 compiler installation instructions for Linux
Gaussian 98 installation instructions for Linux Install WebMO
WebMO installation instructions Copyright © 2001, WebMO, LLC, all rights reserved. Log Boot Disk Creation. 000
# vi smb. D
# vi wu-ftp
      disable = no
# /sbin/service xinetd restart
If ftp fails,make sure that the iphains firewall contains a line for service 21 (ftp) like
      -A input -s 0/0 -d 0/0 21 -p tcp -y -j ACCEPT
that the ftp server software is installed
# rpm -qa | grep wu-ftp
and that either /etc/hosts. Label disk as “Linux 7. Access to services can be restricted to specific IP address. Option A: Manual download and installation of updates Visit the Redhat Errata page and determine which updates should be downloaded and applied
//www. Domain} Gateway: {gateway_address} Primary DNS: {dns1_server_address} Secondary DNS: {dns2_server_address} Firewall Configuration Choose Medium security Choose Customize and allow incoming SSH and WWW(HTTP); if desired, also allow incoming Telnet and FTP Language Support Selection, click Next Time Zone Selection America/Detroit (or your timezone) Leave ‘System Clock uses UTC’ unchecked for Linux/Windows dual boot systems Account Configuration Set root password Add at least one user account Authentication Configuration, accept defaults and click Next Package Group Selection Printer Support Classic X Window System X Window System Gnome KDE Sound and Multimedia Support Network Support Messaging and Web Tools Graphics and Image Manipulation Windows File Server (only if you will run samba) Anonymous FTP Server (not recommended) Web Server Authoring/Publishing Emacs Utilities Software Development Video Card Configuration, accept default video card or choose one manually Preparing to Install. Restart the xinetd daemon for changes to take effect. /install-updates must be run again After the update is complete, restart your computer with
# cd /
# umount /mnt/cdrom
# shutdown -r now
Note that the root file system may fail to unmount during shutdown and is therefore automatically checked upon restart; inodes having zero dtime will be deleted. Microsoft Windows) and must be installed separately as third party software. A log of the update may be found in /tmp/update. Welcome to Red Hat Linux, click Next Install Options, choose Install: Custom Disk Partitioning Choose Manually partition with Disk Druid for easy partitioning, or choose Manually partition with fdisk [experts only] for full control over the partition layout Create the following partitions (sizes suggested): /boot 64MB (only if your computer is pre-1999) swap 1024MB (or twice RAM size) / 8192MB /home 8192MB /scratch 1MB and Click ‘Fill to maximum allowable size’ Accept defaults if satisfied with mount points, filesystem types, and formatting; otherwise, select each partition and click Edit Note: Only 4 primary partitions are allowed. Search for and delete any instances of “Indexes” within “Options” statements, which can be located with
# grep ^[[:space:]]*Options httpd. Suexec imposes many security restrictions upon cgi scripts. 000
# vi hosts
      127. # /sbin/service xinetd restart
Access to the services is further controlled by the /etc/hosts. It is best to allow access for various services to some IP numbers, and then to deny all other access. 000
# vi grub. Thus all user cgi scripts run as the user in whose directory they are installed, instead of as the ‘apache’ user. Xxx (Fills in automatically) Hostname: {hostname. Note that if one properly configures the ipchains firewall, then these access control files are redundant and no changes are needed from the default configuration (empty, which permits access to all services by anyone). Conf If LILO boatloader is being used, verify and/or edit its configuration file, and write changes to hard disk MBR
# cd /etc
# cp -p lilo. It is a certainty that unpatched machines will soon be hacked. 000
# vi httpd. Deny contains no entries or /etc/hosts. Log, and any error messages or warnings may be found in /tmp/update. For example, to accept WWW packets from anywhere, but limit telnet packets to being from the local network, one would use
      -A input -s 0/0 -d 0/0 80 -p tcp -y -j ACCEPT
      -A input -s {network_address}/{subnet_mask} -d 0/0 23 -p tcp -y -j ACCEPT
where {network_address} may be calculated from
$ ipcalc –network {ip_address} {subnet_mask}
{subnet_mask} may also be specified as an integer equalling the number of nonzero bits starting from the left, e. A brief summary of the procedure is given here
Locate your boot floppy disk and verify its operation Backup the previous /boot directory
# mkdir /boot. You may use only one type of firewall, the older default ipchains or the newer iptables. 2 also supports iptables. 000
# cd /boot
# tar cf -. Conf
      In the section, verify that
            UserDir public_html
      Uncomment the section
           . ) Also, some of the services (ssh, sendmail) running as permanent daemons respect /etc/hosts. Sendmail (not recommended)
By default, Red Hat Linux 7. Do not allow outsiders to access sendmail unless you thoroughly understand how relaying works (which permits massive spamming), are prepared to administer an email system, and are willing to accept reponsibility for any spam forwarded by your system. Ss
Write the new date and time to the system’s CMOS clock
# clock -w Verify that all of the machine’s RAM has been detected
$ free
If Linux reports less RAM than is actually installed your system, follow instructions to specify at boot time the amount of available RAM Verify that domainname can be determined
$ hostname -d
If the domainname is not reported, then edit /etc/hosts so that the fully qualified domain name appears before the hostname
# cd /etc
# cp -p hosts hosts. Verify with
$ rpm -qa | grep g77
If it is not present, install it from distribution CDROM disk #2
# rpm -Uhv /mnt/cdrom/RedHat/RPMS/gcc-g77-2. 000
# vi sendmail. Allow files as described below. If access is denied at any level, then the service will appear to fail. This is the last chance to safely cancel the installation process. Com/apps/support/errata/ Check whether or not packages are installed with
# rpm -qa | grep {package} Download the appropriate rpm’s from Redhat
ftp://ftp. Forward
      {[email protected] )
# rpm -Uhv f2c-20000510-5. 2, and therefore one must use the 7. Shares which do not appear may be accessed from Start: Run. To turn on ftp
# cd /etc/xinet. Ssh should be installed by default on Red Hat Linux 7. This can also be done for the xinetd services with the /etc/hosts. Conf
# /sbin/lilo -v Reboot
# /sbin/shutdown -r now Make a new boot floppy disk
# uname -r
# /sbin/mkbootdisk {new_version} Customize Linux Forward root’s email
It is critical that a human actually read root’s email, so that logwatch output, system problems, or security breaches are quickly noted
# vi /root/. Err Kernal upgrades are more complex, and one should definitely read the instructions in The Official Red Hat Linux Customization Guide. Rpm g77
g77 should be installed by default when the Software Development package group was selected during installation. Some administrators prefer to add the apache user to the each user’s group instead of changing each user’s home directory permissions
# vi /etc/group
# vi /etc/gshadow
      {user}:. Allow entry that permits access to all services from a limited IP address range is
      ALL: {network_address}/{subnet_mask}
An example of an /etc/hosts. Ftpd
If access is permitted to specific services as above, then it is recommended that the /etc/hosts. 000
# vi /etc/lilo. /install-updates
Answer ‘y’ to all prompts
If the update fails during the dependency check, then the missing package(s) must be installed manually with
# rpm -ivh 7. Conf
      In the [globals] section
            workgroup = {workgroup}
            server string = {hostname}
      Comment out
            ; printcap name = /etc/printcap
            ; load printers = yes
            max log size = 50
            security = share
            browseable = yes
            oplocks = no
            level2 oplocks = no
            preserve case = yes
            short preserve case = yes
      In the [homes] section
      Add if not present
            valid users = %S
Let samba packets across the firewall
# vi /etc/sysconfig/ipchains
      -A input -s {network address}/{network mask} -d 0/0 137:139 -p tcp -y -j ACCEPT
      -A input -s {network address}/{network mask} -d 0/0 137:139 -p udp -j ACCEPT
Restart the firewall
# /sbin/service ipchains restart
Start the samba server
# /sbin/chkconfig smb on
# /sbin/service smb start
Add the samba share password
# smbpasswd -a {user}
Users may now change their password with
$ smbpasswd
Browse the samba shares from the Windows “Network Neighborhood”. Edit the samba configuration file
# cd /etc/samba
# cp -p smb. D
# vi telnet
      disable = no
# /sbin/service xinetd restart
If telnet fails,make sure that the iphains firewall contains a line for service 23 (telnet) like
      -A input -s 0/0 -d 0/0 23 -p tcp -y -j ACCEPT
that the telnet server software is installed
# rpm -qa | grep telnet-server
and that either /etc/hosts. Forward
      {[email protected] Note that post-Windows 95 machines (Windows 95SE, 98, ME, NT, 2000, XP) must be configured to transmit their passwords as plaintext by modifying their registry as described by the appropriate /usr/share/doc/samba-2. Telnetd
      in. Then restart the xinetd daemon with /sbin/service xinetd restart. Com/pub/redhat/linux/updates/
or from a mirror site
//www. 2 Boot Disk for {hostname}” Monitor Selection and X Configuration Choose specific monitor, or choose and appropriate Generic Monitor Adjust syncronization rates as follows Horizontal sync: 30-64 kHz Vertical sync: 50-75 Hz Customize graphics configuration as follows Color Depth: High Color (16 Bit) Screen Resolution: 1024×768 Desktop Environment: GNOME (default) or KDE (recommended) Login Type: Graphical (for use as workstation) or Text (for use as server by experts) Click ‘Test Setting’ to test X screen settings
NOTE: (Control+Alt+Backspace) exits X immediately Click ‘Next’ Congratulations, Linux has been installed. Rpm
# rpm -ivh –force kernel-pcmcia-cs-{new_version}. One should use sftp instead. Since you probably already have an email account on a centralized server, you do not need to accept email from the outside world on your Linux machine. Some administrators prefer to set “encrypt password = no”, which does not require a separate samba password list to be maintained and allows users to use their Linux passwords to access their files. To do this, comment out
      ; encrypt passwords = yes
      ; smb passwd file = /etc/samba/smbpasswd
in smb. (Note that the Linux 2. D
# vi ipop3
# /sbin/service xinetd restart
# cd /etc
# vi hosts. X configures Samba to use “security=user”, which requires that a user have a Linux account with the same name as their Windows login name, and “encrypt passwords = yes”, which requires that users (or the Linux administrator) maintain a separate samba password list on the Linux machine with the user’s Window’s password that is in general different than their Linux password. Edit these files to disable (disable = yes) or enable (disable = no) these services.            
      Uncomment the line
            AddHandler cgi-script. Conf and restart the samba server. Finally, some services (apache, samba) allow access to be restricted to certain IP addresses through their configurations files. $ cd ~
$ vi. ) The software for the service must be installed on the system, which can be checked with the command rpm -qa | grep {servicename}. Allow permits access by the client
where {network_address} may be calculated from
$ ipcalc –network {ip_address} {subnet_mask} Ftp
Ftp is not generally recommended because login information (username and password) and all files are transmitted as plain text. One should use ssh instead. DOS/Windows requires a primary partition from which to boot, and additional drives must be logical partitions. Rpm from the Red Hat Linux 7. Allow entry that permits access to ssh from anywhere is
      sshd: ALL
Other services controlled by these access files include
      in. The default firewall is defined in /etc/sysconfig/ipchains, which was created during Firewall Configuration step of the installation process. Rpm
Verify that symbolic links are correct
# ls -lF /boot If you have a SCSI hard disk, verify that a new disk image file was created
# ls -l /boot/initrd* If GRUB bootloader is being used, verify and/or edit its configuration file
# cd /boot/grub
# cp -p grub. Insert disk 2 when prompted and click OK. In order for apache to access a user’s www files, the user’s home directory must be set to mode 711 and the public_html subdirectory must be set to mode 755. Insert formatted floppy and click Next. A log will be written to /tmp/install. When troubleshoting access to services, you need to consider all of the above factors. This is done most fundamentally in the firewall configuration file, which can be configured to only allow access to certain services (ports) by certain IP address ranges. 000; tar xvf -) Note what version of the kernel you are currently running
# uname -r Note what current kernel components are installed
# rpm -qa | grep kernel- Install new versions of the kernel components (only if they were already installed), using -U or –force options if necessary
# rpm -ivh kernel-{new_version}. Rpm} Restart your computer so that new versions of any updated services are restarted
# /sbin/shutdown -r now Option B: Purchase Official Red Hat Update CD-ROM and automatic installation of updates
Order the most recent Update CD from
//www. 1+ configures sendmail to only accept mail from the localhost, which should be fine in almost all cases. Cgi
      Add the lines
            Options ExecCGI
            SetHandler cgi-script
It is recommended that directory browsing be disabled. 4 kernel in Red Hat Linux 7. Edu} Create useful mount points, for example
# mkdir /mnt/zip
# mount -t vfat /dev/hdd4 /mnt/zip
# ls -alF /mnt/zip
# umount /mnt/zip
If the following line is added to /etc/fstab
      /dev/hdd4   /mnt/zip   vfat   noauto,owner   0 0
then the mount command can be simplified to
# mount /mnt/zip Turn on desired services Understand background concepts about access to services
Access to system services over the network is controlled at multiple levels:
A firewall controls what packets are accepted by the system and which are dropped or rejected. Cf
Allow external access to sendmail
# cd /etc
# vi hosts. An example of an /etc/hosts. The syntax of this file is explained in the ipchains man page and on the many websites devoted to explaining ipchains and firewalls. Deny file consist of
      ALL: ALL
The efect of these entries is immediate, and the xinetd daemon does not need to be restarted after making changes. Remove floppy, click Exit, and remove CD-ROM to reboot Verify aspects of the system configuration Verify the date and time
$ date
Adjust the date and time if necessary
# date MMDDhhmm[YYYY]. D and setting disable=no. Html Install the updates
# rpm -Fvh {package-version. Allow permits access by the client
      sshd:ALL Apache
The apache web server runs as the “apache” user in Red Hat Linux 7. However, ftp is sometimes used on a secure local network when security is less of a concern. One of these may be an extended partition, which can contain up to 12 logical partitions. Install additional packages and software f2c
Obtain f2c-19991109-2. Rpm
Edit the sendmail configuration file
# cd /etc
# cp -p sendmail. Edu}
If you do wish to set up pop3 or other mail retrieval services, do the following:
Install the imap package from distribution CDROM #2
# rpm -Uhv /mnt/cdrom/RedHat/RPMS/imap-2000c-15. Rpm
Allow external access to pop3 (and/or pop3s, imap. D
Filenames in this directory correspond to services that are controlled by the internet services daemon (formerly known as tcp_wrappers). Allow
# cd /etc/sysconfig
# vi ipchains
      -A input -s 0/0 -d 0/0 25 -p tcp -y -j ACCEPT
# /sbin/service ipchains restart
Restart sendmail
# /sbin/service sendmail restart Pop3 and imap (not recommended)
These mail access agents are probably only needed if sendmail has been set to allow access from other computers, i. It is often preferable to limit accepted packets to the local network, rather than accept them from anywhere. This configuration is appropriate only for a system which operates on a secure local network, as the password is transmitted as plaintext (like telnet and ftp). Check whether anonymous ftp is installed with with
$ rpm -qa | grep anonftp
If so, turn off anonymous access to your Linux machine by adding the following lines to the ftp configuration files
# cd /etc
# cp -p ftpaccess ftpaccess. 000
# cd /etc/mail
# cp -p sendmail. Some older BIOS limitations require that the Linux /boot directory be contained in its own partition which does not extend beyond cylinder 1024. Mc
      dnl DAEMON_OPTIONS(`Port=smtp,Addr=127. If you do need to set up a centralized email server on your system, do the following:
If necessary, install the sendmail configuration file package from distribution CDROM #1
# rpm -Uhv /mnt/cdrom/RedHat/RPMS/sendmail-cf-8. Localdomain   localhost Install update packages from RedHat It is critical that any security related updates be applied to your system. Therefore, one must manually do a ‘chmod 755′ on any directory containing cgi scripts. X as well as Fedora. 1, Name=MTA’)
# m4 sendmail. Allow and then deny all other access in hosts.

Red Hat Enterprise Linux (RHEL) 6 Installation Guide with ...

Because it is a moving target, packages built for Amazon Linux tend to break at inopportune times. While it uses the RPM packaging format, it is a rolling-release distribution that is not compatible with RHEL/CentOS or Fedora. Amazon Linux is not supported. Because of its inherent instability, using Amazon Linux is not recommended for any project that requires stability, not just Bitcoin.

This match option can also be reversed with the exclamation point character (. UDP Protocol These match options are available for the UDP protocol (-p udp): •. Chapter 18:Firewalling with iptables • –tcp-option Attempts to match with TCP-specific options that can be set within a particular packet.

In the generic command above, the first argument is the priority value to be used, whereas the other argument can be interpreted as process IDs (which is the default setting), process group IDs, user IDs, or user names. A normal user (other than root) can only modify the scheduling priority of a process he or she owns, and only increase the niceness level (which means taking up less system resources).

Linus Torvalds and others on Linux's systemd | ZDNet

3 Directories in /proc Common groups of information concerning the kernel is grouped into directories and sub-directories within /proc. Chapter 4:The /proc Filesystem This information is used for a variety of purposes, including providing the version data at the standard login prompt.

3:Options Used in iptables Commands • –limit-burst — Sets a limit on the number of packets able to match a rule at one time. This option should be used in conjunction with the –limit option, and it accepts a number to set the burst threshold.

Typical output for this file looks like this: The first and last values set the minimum and maximum percentage of memory to be used as buffer memory, respectively. Chapter 4:The /proc Filesystem • buffermem — Allows you to control the percentage amount of total system memory to be used for buffer memory.

• no_access — Blocks these hosts from using this service. 3:Access Control Using xinetd The following options are supported in the xinetd files to control host access: • only_from — Allows the hosts specified to use the service.

) in the /etc/systemd/system/multi-user. This tells systemd to start everything in the /usr/lib/systemd/system/basic. Target, all units (services, targets, etc. When you enable a service, a symbolic link is placed in the /etc/systemd/system/multi-user. Wants directories are started. That directory is where you will find links to most of the services you think of as starting in multi-user mode (printing, cron, auditing, SSH, and so on). Target target before starting the other multi-user services. Here is an example of the services, paths, and targets in a typical multi-user. After that, for the multi-user.

red hat enterprise linux 7 boot process

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