How to restrict su from root-to-nis-clients

Yes, there is a way to restrict this behaviour. This behaviour of su is governed by the PAM module (Plugable Authentication Module):

You must edit /etc/pam.d/su

comment the line :

auth       sufficient pam_rootok.so

like this:

#auth       sufficient pam_rootok.so

after that su from root will ask for the user password.

Environment variables for java installation

Java SE Development Kit 8u112 on a 64-bit Windows 7 or Windows 8

 

Enter the Variable name as JAVA_HOME and the value to your jdk bin path ie c:\Programfiles\Java\jdk-1.7\bin

Follow the Above step and edit the Path in System Variables add the following ;c:\Programfiles\Java\jdk-1.6\bin in the value column

Your are done setting up your environment variables for your Java , In order to test it go to command prompt and type

 java  

who will get a list of help doc

In order make sure whether compiler is setup Type in cmd

  javac

set JAVA_HOME=C:\Program Files\Java\jdk1.8.0_144\jre\bin

 

set.SERVER_NAME=server0

Enable credential cache on Linux AD integration using sssd

Enable credentials caching; this allows users to log into the local system using cached information, even if the AD domain is unavailable.

Raw

cache_credentials = true

Find Out What Is Using TCP Port 80

Use /proc/$pid/exec file find out what is using port 80

First, find out the processes PID that opened tcp port 90, enter:

# fuser 80/tcp

Sample outputs:

80/tcp:              12161 21776 25250 25393

Finally, find out process name associated with PID # 3813, enter:

# ls -l /proc/12161/exe

Sample outputs:

lrwxrwxrwx. 1 root root 0 Aug  9 17:08 /proc/12161/exe -> /usr/sbin/light

IP Addressing and Classes

IP - Internet Protocol

IP or IP address is a number i.e. ( 216.58.216.165 ) used to indicate the location of a computer or other device on a network.

IP address classes

IPv4 IP address, there are five classes of available IP ranges:
Class A
Class B
Class C
Class D
Class E

Only A, B, C are commonly used.

Each class has its range of valid IP addresses are shown below :
Class Address Range Supports
Class A 1.0.0.1 to 126.255.255.254 Supports 16 million hosts on each of 127 networks.
Class B 128.1.0.1 to 191.255.255.254 Supports 65,000 hosts on each of 16,000 networks.
Class C 192.0.1.1 to 223.255.254.254 Supports 254 hosts on each of 2 million networks.

ReadMore..
IP - Internet Protocol

IP or IP address is a number i.e. ( 216.58.216.165 ) used to indicate the location of a computer or other device on a network.

IP address classes

IPv4 IP address, there are five classes of available IP ranges:
Class A
Class B
Class C
Class D
Class E

Only A, B, C are commonly used.

Each class has its range of valid IP addresses are shown below :
Class Address Range Supports
Class A 1.0.0.1 to 126.255.255.254 Supports 16 million hosts on each of 127 networks.
Class B 128.1.0.1 to 191.255.255.254 Supports 65,000 hosts on each of 16,000 networks.
Class C 192.0.1.1 to 223.255.254.254 Supports 254 hosts on each of 2 million networks.

ReadMore..
http://magazie.co.in/ip-addressing-and-classes/