Linux iptables as a Router
Netfilter : The actual filtering in a Linux box is done using Netfilter. Iptables : is the tool used to create this filters. Iptables maintain state-full firewall. Ipchains does not maintain state-full firewall The module…
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NIS : Network Information Service
An NIS system maintains and distributes a central directory of user and group information, hostnames, e-mail aliases and other text-based information in a network. Though not the core purpose, NIS can be used for centralized…
NFS : Network File System
A network file system is a computer file system that supports sharing of files, printers, etc over a computer network. Package : nfs-utils.rpm Configuration file : /etc/exports Daemon : nfs Procedure to share a folder…
Linux SSH (Secure Shell)
SSH is a network protocol. It allows data to be exchanged using a secure channel between two networked devices. Same protocol is used for: ssh sftp scp RPM packages required to rum ssh includes: Openssh.rpm…
File Transfer Protocol (FTP)
Package: vsftpd—-.rpm Configuration file: /etc/vsftpd/vsftpd.conf Package: ftp (client) Two types of login: (a) Anonymous login: Anyone can login using the username “anonymous” or “ftp”, with password field blank. Here the user will be restricted to…
Bind DNS Service
DNS is a structured database system that maps a computer’s fully qualified domain name into an IP address. Computers in a network use IP addresses to locate and connect to each other, but IP addresses…
Linux SWAP Memory
Listed delow is the procedure to create a swap space in Linux: # fdisk /dev/sda : Create a partition in Linux # mkswap -v1 /dev/sda10 : Make and format swap partition using this command #…
Redhat Linux User Administration (RHEL 4)
User ID = uid. The uid of root is 0. UID from 1 to 499 is reserved for system services such as the user apache, nagios, etc The first user created by root will always…
Redhat Package Manager (RPM)
Set of binary files, which are compiled programs. This is similar to add/remove programs in windows. RPM is used to manage installation packages including installation and un-installation. The database that contains information of all rpms…
Linux File Attributes
Listed below are few attributes that can be assigned to a file: # chattr +i /etc/passwd : i = immutable (cannot remove, edit, rename or move) # chattr -i /etc/passwd : Remove the above…