Category Archives: Networking

how to firewalld

“Firewalld provides a dynamically managed firewall with support for network/firewall zones that define the trust level of network connections or interfaces. It has support for IPv4, IPv6 firewall settings, ethernet bridges and IP sets. There is a separation of runtime and permanent configuration options. It also provides an interface for services or applications to add firewall rules directly.” – firewalld.org

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Setup BIND DNS Server on CentOS 7

Setup BIND DNS Server on CentOS 7

This tutorial provides an example how to Setup BIND DNS Server on CentOS 7.
This example is suited for secure private networks behind a gateway.

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Test firewall with netcat

Overview

“The nc (or netcat) utility is used for just about anything under the sun involving TCP, UDP, or UNIX-domain sockets.
It can open TCP connections, send UDP packets, listen on arbitrary TCP and UDP ports, do port scanning, and deal with both IPv4 and IPv6. Unlike telnet nc scripts nicely, and separates error messages onto standard error instead of sending them to standard output, as telnet does with some.” (NetCat Manual)

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DD-WRT set date manually

dd-wrt set date manually

dd-wrt set date manually – In this tutorial I’ll explain how to set the date and time in dd-wrt based routers.

 

dd-wrt set date manually

My dd-wrt system is dd-wrt v24-sp2 (11/02/09) std
(SVN revision 13064M VINT Eko).

It may not work on your system but I’ll explain the basics so you should be able to find your own way.

 

dd-wrt set date manually

in dd-wrt set date manually using command-line. you can do this by:

  • SSH to your dd-wrt machine, or
  • use the web interface to run command line

Becuase ssh is not opened by default on all dd-wrt machines I’ll explain how to set the date and time using the second method – using the web interface. but the same command and rules apply also to SSH connection.

 

Admin Panel

go to your dd-wrt admin managment panel on your browser and view the Administration / Commands page. it may be different in your system version but you should able to find quickly where the Commands page is.

dd-wrt set date

dd-wrt set date

Date

You can use the Date command inside your dd-wrt box to read and set your system time and date.

View current date (NOW)

to view your current date as configured in your dd-wrt machine use the ‘date‘ command.
Just fill the commands input box with ‘date’ and click on the ‘Run Commands‘ button.

date

dd-wrt-date

 

dd-wrt set date manually

Here it may be tricky. I’ve found several online blogs and manuals but nothing worked. to set the dd-wrt date manually I’ve succeded with the following command:

date 022720012014

Month Day Hours Minutes Year
02 27 20 01 2014

 

 

dd-wrt-set-date

 

that’s it. I hope It helped you to configure your dd-wrt set date manually.

iptables examples on CentOS

Overview

“iptables is a user space application program that allows a system administrator to configure the tables provided by the Linux kernel firewall (implemented as different Netfilter modules) and the chains and rules it stores.
Different kernel modules and programs are currently used for different protocols; iptables applies to IPv4, ip6tables to IPv6, arptables to ARP, and ebtables to Ethernet frames.”

In this tutorial I will give a few essential examples of how to use iptables on CentOS
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OpenVPN ALS Adito SSL VPN Gateway on CentOS

Overview

OpenVPN ALS Adito SSL VPN Gateway is a web-based SSL-VPN server written in Java and it is completely free and open-source.
The installation on CentOS 6 Linux Operating System is fairly simple using the next few steps (we will use CentOS Minimal x86_64).
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Configure DD-WRT Router as an Access Point or Wireless Repeater

Overview

This tutorial will explain how to use your DD-WRT router as a Repeater or Access Point.

“DD-WRT is a Linux based alternative Open-Source firmware suitable for a great variety of WLAN routers and embedded systems.
The main emphasis lies on providing the easiest possible handling while at the same time supporting a great number of functionality within the framework of the respective hardware platform used.”

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