Skip to main content

Installation of ns3 in Ubuntu | Ubuntu 24.04 | ns-3.42

How to open Ports in CentOS using i-tables

CentOS is the most preferred alternative OS for RHEL. Those who cannot afford to purchase the support license of RHEL, they can use CentOS that comes with almost similar to RHEL.

This post tells you about the usage of CentOS when web servers are installed and accessed from remote machines.

CentOS is a Server based OS and most of the ports are closed by default and you need to open it for access from outside (remote).
For ex. if wordpress is installed in CentOS with a hostname  which is very well accessed within the server. When the same is tried from outside like (, then it will not get accessed.
The problem is the closure of ports in CentOS. So you need to open it and save it to iptables, here are the commands that will help you to do that.


Port number : 80 is used here

$prompt] ifconfig (find out which interface uses the assigned ip, eth1, eth0, etc)

$prompt] iptables --line -vnL
(See which line the input has to be accepted and in my case it is 6) and give the following command

$prompt] iptables -I INPUT 6 -i eth1 -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT

$prompt] service iptables save (Save and restart the IP Tables)

$prompt] service iptables restart

Thats all!!!! I solved this problem, when I installed MOODLE in my Blade server with Cent OS installed.

Pradeep Kumar TS


Popular posts from this blog

Installing ns3 in Ubuntu 22.04 | Complete Instructions

In this post, we are going to see how to install ns-3.36.1 in Ubuntu 22.04. You can follow the video for complete details Tools used in this simulation: NS3 version ns-3.36.1  OS Used: Ubuntu 22.04 LTS Installation of NS3 (ns-3.36.1) There are some changes in the ns3 installation procedure and the dependencies. So open a terminal and issue the following commands Step 1:  Prerequisites $ sudo apt update In the following packages, all the required dependencies are taken care and you can install all these packages for the complete use of ns3. $ sudo apt install g++ python3 python3-dev pkg-config sqlite3 cmake python3-setuptools git qtbase5-dev qtchooser qt5-qmake qtbase5-dev-tools gir1.2-goocanvas-2.0 python3-gi python3-gi-cairo python3-pygraphviz gir1.2-gtk-3.0 ipython3 openmpi-bin openmpi-common openmpi-doc libopenmpi-dev autoconf cvs bzr unrar gsl-bin libgsl-dev libgslcblas0 wireshark tcpdump sqlite sqlite3 libsqlite3-dev  libxml2 libxml2-dev libc6-dev libc6-dev-i386 libclang-dev llvm-

Installation of NS2 (ns-2.35) in Ubuntu 20.04

Installation of NS2 (ns-2.35) in Ubuntu 20.04 LTS Step 1: Install the basic libraries like      $] sudo apt install build-essential autoconf automake libxmu-dev Step 2: install gcc-4.8 and g++-4.8 open the file using sudo mode $] sudo nano /etc/apt/sources.list Include the following line deb bionic main universe $] sudo apt update $] sudo apt install gcc-4.8 g++-4.8 Step 3:  Unzip the ns2 packages to home folder $] tar zxvf ns-allinone-2.35.tar.gz $] cd ns-allinone-2.35/ns-2.35 Modify the following make files. ~ns-2.35/ Change @CC@ to gcc-4.8 change @CXX@ to g++-4.8 ~nam-1.15/ ~xgraph-12.2/ ~otcl-1.14/ Change in all places  @CC@ to gcc-4.8 @CPP@ or @CXX@ to g++-4.8 open the file: ~ns-2.35/linkstate/ls.h Change at the Line no 137  void eraseAll() { erase(baseMap::begin(), baseMap::end()); } to This void eraseAll() { this->erase(baseMap::begin(), baseMap::end()); } All changes made Step 4: Open a new termi

Installation of NS2 in Ubuntu 22.04 | NS2 Tutorial 2

NS-2.35 installation in Ubuntu 22.04 This post shows how to install ns-2.35 in Ubuntu 22.04 Operating System Since ns-2.35 is too old, it needs the following packages gcc-4.8 g++-4.8 gawk and some more libraries Follow the video for more instructions So, here are the steps to install this software: To download and extract the ns2 software Download the software from the following link Extract it to home folder and in my case its /home/pradeepkumar (I recommend to install it under your home folder) $ tar zxvf ns-allinone-2.35.tar.gz or Right click over the file and click extract here and select the home folder. $ sudo apt update $ sudo apt install build-essential autoconf automake libxmu-dev gawk To install gcc-4.8 and g++-4.8 $ sudo gedit /etc/apt/sources.list make an entry in the above file deb bionic main universe $ sudo apt update Since, it&#