The Linux Juggernaut

We are very much happy to announce that we started posting on DNS client and Server stuff on our blog for this month(Jan 2011). We already have some minor existing stuff related to DNS and troubleshooting it. Below are quick links to our existing DNS Server/Client stuff

http://www.linuxnix.com/tag/dns-servers

http://www.linuxnix.com/tag/dns

Some of the DNS topics which are going to cover in this month are as follows. Please feel free to add requirements for DNS concepts which are not … Continue Reading

In our previous post we written about dot at the end of permissions this is one more special permissions where you will find + at the end of permissions field in ls -l command output.

This is actually a small post, which is asked by one of the requester. This is a special permission in Linux which inidicates that ACL(Access Control List) is implemented on that file/folder. Some times you will be seeing +(Plus) at … Continue Reading

Q. Today I am came across a strange permissions listing ie dot, What is meant by dot in file/folder permissions in drwxr-xr-x in Linux?

This is actually a small post, which is asked by one of the requester. This is a special permission in Linux which is recently included. Some times you will be seeing dot at the trailing end of permissions

Example:

ls -l Videos

drwxr-xr-x. 3 surendra surendra 4096 2011-07-06 00:19 Videos… Continue Reading

SSH communication works on two principles
1)Communication should be done in encrypted channel
2)This encryption can be done by exchanging a PUBLIC KEY between two parties and a PRIVATE KEY for decrypting the data.
So how SSH communicate works?
When SSH package is installed on any machine a PUBLIC KEY and A PRIVATE KEY will be generated or installed by default on it.
Lets explain this with an example.
I have two machines … Continue Reading

We can always set time to the commands showed in history command. Why we require to set time for this?

This is totally a security measure and used for troubleshooting/fingerprinting a security threat.

history command sample output before setting this variable.

 466  df -h
 467  df 
 468  exit
 469  nfsstat 
 470  find / -iname *.ppt
 471  ftp2
 472  man ping
 473  ping -R google.com

So how to set that?

Use inbuilt variable HISTTIMEFORMAT to set … Continue Reading

IPtable is a firewall application by default installed in all the Linux flavors. It is having great capabilities in blocking and unblocking content. To disable iptables in Redhat/CentOS we have to use the following commands

#service iptables stop

#service iptables save

#chkconfig iptables off

To be more meaning full way to stop iptables on all the run levels use below commands.

#chkconfig --level 123456 iptables off… Continue Reading