Linux solutions

FTP is used to transfer files between computers on a network. You can use FTP to exchange files between computer accounts, transfer files between an account and a desktop computer, or access online software archives. =>   Install     vsftpd for   FTP Server =>    #yum install vsftpd.x86_64 –y =>  Then   start the service =>  #systemctl start vsftpd =>  Now check the status =>  #systemctl status vsftpd   =>  #Now check ftp server working or not    =>  #firefox ftp://192.168.1.10( Server IP)    => Now you will able to see the data on ftp server Thank You...

=> What will be the ownership of files owned by a deleted use? => How to change user’s home direcroty, login shell, uid , gid etc? =>  How to set ACLs so that the directory’s created in a ACL applied directory get inherited ACLs set? =>  Explain /etc/default/useradd =>  How to assign a duplicate uid to a user ? =>  How to recover a corruted/damaged password file ? =>  pwconv and pwunconv command? => H ow will you differentiate a primary and secondary group? =>  How to add more than one secondary group to user ? =>  finger command? =>  How to force a user to change its password on first login attempt? =>  Can you edit /etc/passwd, /etc/shadow and /etc/group files ? =>  What is configuration file for sudo and how to write in it ? =>  How to assign sudo access to a user ? =>  What is the meaning for three ALLs in assigning sudo access ? =>  How to assign the sudo access ...

An email message is created using a mail client program. Mail is digital messaging service and which generally consists of a message body . =>   These are the most commonly used in the transfer of email Simple Mail Transport Protocols (SMTP-Port 25) delivery from a client application to the server, and from an originating server to the destination server, is handled by the  Simple Mail Transfer Protocol  ( SMTP ). =>  Mail Access Protocols POP (Post Office Protocol):  -( P ort 110 ) It  is an email accessing protocol used to receive mails from a mail server and  POP  will download all emails from the server to the user’s computer. IMAP (Internet Message Access Protocol):- ( Port 143 ) It   is another email accessing protocol however it is used to access the mails from the server.IMAP will synchronize a copy of the mail on the server to the user’s computer. All mail data is kept on the server as well as the user’s computer until they ...

=>   How to check the machine’s architecture ? =>   How to check the current kernel version running ? =>   How to see whether a module is loaded or no ? =>   How to load/unload a module ? =>   Where are kernel modules stored ? =>   How to find information about a module ? =>   How to upgrade your kernel ? =>   How to set kernel parameters?

=>  Samba provides server and client software to allow file sharing between Linux and Windows machines. => Default Port : "445" => Daemon : "smb" => Install SAMBA Server   =>  # yum install samba* -y => Enable the samba service =>  #systemctl enable smb => Now start the service =>  #systemctl start smb => Disable the firewall or add the samba port =>  #systemctl stop firewalld =>  #systemctl disable firewalld => Create directory for sharing =>  #mkdir shared_folder => Assign full permission   =>  #chmod 777 shared_folder/ => Create users  =>  #adduser sam =>  #adduser tom => Make users as "samba" users =>  #smbpasswd -a sam =>  #smbpasswd -a tom => Configure the samba file   =>  #vim /etc/samba/smb.conf => Add the following lines :  => Save and exit => Restart samba services =>  #systemct...

 

 

 

=> Reboot System => Insert DVD (in case you have virtual machine) => #reboot => Select "Troubleshooting" => Now choose the "Rescue a Red Hat Enterprise Linux system" => After some time you will see the bellow screen : => Type "1" for continue and press the enter button => Press ENTER Button to get a shell => After the enter you will get the bellow mention shell => Run Command  =>  sh-4.4#chroot /mnt/sysimage => Now Run command for restore grub file:   =>  sh-4.4#grub2-mkconfig -o /boot/grub2/grub.cfg => Now exit from the cell =>  sh-4.4#exit => Now system will restart automatically and grub file restoration done.

=>  Create Directory   =>  # mkdir /yum => Insert DVD  =>  Check DVD Path => # df -h =>  Go To dvd directory  =>   # cd /run/media/server/RHEL-8-3-0-BaseOS-x86_64 =>  Check dvd data  =>  # ls =>  Copy "AppStream" directory and " BaseOS" Directory  =>  # cp -R BaseOS /yum/ =>  # cp -R AppStream /yum/ =>  Go To created Directory and Check data =>  # cd /yum =>  Go To "yum.repos.d" directory =>  # cd /etc/yum.repos.d/ =>  Create a appstream.repo and baseos.repo file  =>  # vi appstream.repo Save and exit. =>  # vi baseos.repo =>  Check yum list =>  # yum list =>  Now you can install any services using yum. Now yum installed.

=>  Link,tar Compression =>   Network Configuration =>   Network Bonding =>   SSH =>   PXE Boot Server =>   SAMBA Server =>   Boot Process =>   Mail Server =>   Partition & Swap =>   LVM =>   Package Management =>   User and Group Management =>   Permissions =>   Log Server =>   NSF & AUTOSF =>   Selinux & Services =>   Firewalld =>   Managing process =>   System and Network Monitoring =>   Kernel & Tuning =>   Kick Start =>   Sudo =>   NTP Server =>   Apache Server =>   Cache only DNS Server

   SSH (Secure Shell) :- => It is a protocol which facilitates secure communications between two  systems using a client-server architecture and allows users to log in  to server host systems remotely. => Unlike other remote communication protocols, such as FTP or Telnet,  SSH encrypts the login session, rendering the connection difficult for  intruders to collect encrypted passwords. => SSH Protocol was developed in 1995 by Tatu Ylonen, Finland . => Packages:-   openssh => Port Number:-  TCP 22 (Default Port) => Main Config File:-   /etc/ssh/sshd_config => Daemon Name:- sshd   SSH CONFIGURATION FILES :- => sshd_config - The configuration file for the sshd daemon. => sshd_host_dsa_key - The dsa private key used by the sshd daemon. => authorised_key - This file holds a list of authorized public key for Servers. When the Client connect to a server, the server authenticates the Client by c...

 What is IP :- => IP stands for internet protocol. => IP is main protocol responsible for routing packets across networks, including the internet. => IPv4 is mostly responsible for routing packets on modern networks. => IPv6 will soon evolve as primary protocol used for this purpose as all the IPv4 addresses have been allocated.  Subnet mask : -    => Each IP address is made up of two pieces    1.Network portion-defines the network address-what network to route to?     2.Host portion-defines hosts on that specific network => A subnet masks is  a 32-bit number that  tells the router which bits of the IP address are for the network portion and which bits for host portion => Subnet mask is a binary number but is also usually communicated  in dotted decimal format => Example-11111111.11111111.11111111.00000000     Example is dotted decimal format-255.255.255.0  IP address classes: ...