IPTABLES & FIREWALL - 3

IPTABLES / FIREWALL INTERVIEW QUESTIONS AND ANSWERS

                                                     PAGE - 3

      21..How to check iptables service?

       # service iptables status

       # iptables -F

       # service iptables stop

       # chkconfig iptables off

     22. How do I disable firewall?

      # service iptables save
      # service iptables stop
      # chkconfig iptables off

     

      23..How to delete  iptable rules?

     # iptables –F

     24..How to start iptable?

     #  service iptables start

       

     25..How to  stop iptables?

     

     # service iptables  stop

26..How to list the  iptables rules?

#  Iptables –L

27..What is  Load balancing?

Load balancing involves distributing connections across a group of servers so that higher total throughput can be achieved. One way to implement simple load balancing is to set up port forwarding so that the destination address is selected in a round-robin fashion from a list of possible destinations.

28.. What are the Linux-based security tools?

Selinux
Firewall
iptables
Tcp-wrappers

29..How u use the iptable firewall to restrict ssh,telnet,ftp?

For SSH
iptables -A INPUT -s -p tcp --dport <22> -j
REJECT/DROP/DENY

For Telnet
iptables -A INPUT -s -p tcp --dport <23> -j
REJECT/DROP/DENY

For FTP
iptables -A INPUT -s -p tcp --dport <21> -j
REJECT/DROP/DENY

30..How to drop packets using iptables ?

Iptables -A INPUT -s xx.xx.xx.xx -d xx.xx.xx.xx -j DROP

rgin-bottom:.0001pt;line-height:normal; mso-layout-grid-align:none;text-autospace:none'>For SSH
iptables -A INPUT -s -p tcp --dport <22> -j
REJECT/DROP/DENY

For Telnet
iptables -A INPUT -s -p tcp --dport <23> -j
REJECT/DROP/DENY

For FTP
iptables -A INPUT -s -p tcp --dport <21> -j
REJECT/DROP/DENY