Cheap international phone calls using Asterisk/FreePBX and local numbers

One of the easiest ways to make cheap international phone calls is to set up a local access number that automatically forwards to an international number using VOIP.

This is a great way to keep in touch with friends and family in other countries (or to let them keep in touch with you!)

It’s very simple to do in FreePBX in two easy steps.

Create a Misc Destination for the number you want to call -

then create an Inbound Route with your local number as the DID Number -

and set the destination to your Misc Destination -

You can then call the local number and be connected to the international number, only paying inexpensive VOIP rates. The local number can be dialled in the normal way, including from a mobile phone.

Give it a go by ringing this London number – 020 3455 4080 – which will connect you to the Naval speaking clock in Washington DC.

If you’re looking for free UK local numbers then try here – http://www.ukddi.com/

Related posts: Cheap international phone calls with AsteriskGetting started with FreePBX – Part 6 Cheap phone calls using DISA and Callbackvoip.ms with Asterisk

Switchvox Mobile on your iPhone or Blackberry

Are you mobile?  Do your clients have to juggle 2 or more phone numbers to reach you because you are sometimes at your desk but most of the time all over the place?  Don’t you wish your business card were a little less cluttered with just one contact phone number that you can be reached at all the time?  You can have these things now, and you probably won’t even have to buy anything!

Businesses running Switchvox 4.6 or 4.5 already have the ability to stream the Switchvox desktop phone functionality to iPhones and Blackberries.  If you are using Switchvox for your desktop phone system and you have an iPhone or a Blackberry, you are less than 10 minutes from enjoying all the features your desk phone has to offer on your SmartPhone!

Ready? Let’s get mobile!

Once you enter the App store, search for Switchvox Mobile.  This App is a FREE DOWNLOAD!!!! (Don’t you just love FREE)

Switchvox Mobile for Blackberry

-          For Blackberry go to www.BlackBerry.com/AppWorld 

-          For iPhone go to www.apple.com/iphone

(This is neat…. If you don’t have Switchvox yet, but want to see how Switchvox mobile works, you can download the App and use it in DEMO mode!!!! )

-iPhone Users – click here for easy to follow instructions on how to set up your iPhone for Switchvox Mobile (with Pictures!)

-BlackBerry Users – click here for easy to follow instructions on how to set up your Blackberry for Switchvox Mobile

See details, listen to your voicemails, and return calls at the touch of a button.Access your Switchvox Company directory without logging into the internet.Remotely set your greetings without a chain of touch-tone commands.Make calls out either from your SmartPhone number or your Switchvox extension.Set up call rules using an easy GUI while away from the office.See call history from your SmartPhone while nowhere near your desk. Even see call history on your SmartPhone for calls you made from your desk!

Using IP tables to secure Linux server against common TCP hack attempts

In the innocent communication world of TCP/IP, when using TCP protocol the communication starts with something called a three way handshake. Both parties assume that the other party is as innocent as it is itself. First party/computer sends a message called SYN to any IP address in the world. The computer/server which receives it and even not knowing who has sent this message, sends back a reply message called SYN-ACK and innocently starts waiting for the final reply from the sender (note that it waits, assuming that the sender will send a final reply). The sending computer upon receiving this reply and following the ethics of TCP/IP communication sends back the final reply message called ACK. This completes the three way hand shake which establishes a connection between these two computers and they start exchanging data between each other.

Computer1 -> SYN -> Computer2
Computer2-> SYN-ACK -> Computer1
Computer1 -> ACK -> Computer2

Now if the first computer simply starts sending a lot of SYN messages to a computer or multiple computers, and on receiving back the SYN-ACK replies never reply back with the final ACK message to any of the computers, then these poor computers who are replying back with the SYN-ACK messages will keep waiting for the final ACK message from the sender computer. The purpose of this attack is to flood a server with so many SYN packets that it starts ignoring incoming request from legitimate users.

Computer1 -> SYN -> Computer2
Computer2 -> SYN-ACK -> Computer1
Computer1 -> No rpely. Poor Computer2 waiting for reply
Computer1 -> another SYN -> Computer2
Computer2 -> SYN-ACK -> Computer1
Computer1 -> No rpely. Poor Computer2 now waiting for two replies
and so on

So make sure that on your system all the NEW incoming tcp connections are SYN packets; otherwise we need to drop them:

iptables -A INPUT -p tcp ! --syn -m state --state NEW -j DROP

DROP FRAGMENT PACKETS

Packets with incoming fragments drop them. This attack result into Linux server panic such data loss.

iptables -A INPUT -f -j DROP

XMAS PACKETS

Incoming malformed XMAS packets drop them:

iptables -A INPUT -p tcp --tcp-flags ALL ALL -j DROP

DROP ALL NULL PACKETS

Incoming malformed NULL packets:

iptables -A INPUT -p tcp --tcp-flags ALL NONE -j DROP

Filter ICMP/PING traffic

Pinging public IP addresses is a common way to find out which IP address is live. Pinging is a process in which a computer echoes back whatever data it receives. This is why in technical terms it is called an echo-request and echo-reply mechanism which works over ICMP protocol. An attacker can also send a computer with the largest possible TCP packet, i.e. 64Kb packet and the computer will reply back with a packet of the same size. Its an easy way to clog a server’s bandwidth and processing power. So its a good idea to either block all the ping requests or let them work only for the selected IP addresses. To block all the ping requests:

iptable -A INPUT -p icmp -j DROP

To exclude some IP address, e.g. 74.125.148.10:

iptable -A INPUT -p icmp -s ! 74.125.148.10 -j DROP

If you remove the ‘!’ sign before the IP address, it’ll mean that only this IP address can’t ping this server, but all the rest of the world can. Using the same way you can block the whole blocks of IP addresses.

How To Set Up A Wireless Network Using WPA/WPA2 With Radius Authentication With CIITIX-WiFi

Other Preface

For more documentation downloads and support head to http://ciitix.ciit.net.pk and remember to check out the forums. This document serves as quick guide on how to set up a wireless network using WPA / WPA2 with radius authentication. This document will only cover the basics and is not exhaustive of all possibilities and features but with this information and basic networking skills you should be able to get running very soon. No knowledge if Linux is assumed in this guide and for the most part its spelled out with screen shots.

I'd like to thank the team who created this easy way of implementing radius authentication for WiFi and believe it's the only package around which is aimed at a turn key solution meaning no compiling, setting up databases and the like. After all everyone has enough to worry about keeping there IT infrastructure working. I decided to do this guide for the users wanting to try out and implement radius authentication for WiFi security. This project is still very new, and at time of writing the latest version is v1.1.

 

Prerequisites

1) You have downloaded the ISO file and have that ready to install; see http://ciitix.ciit.net.pk for downloads.

2) You have an access point / wireless router which is capable of WPA / WPA2 enterprise setup.

3) Basic networking skills and computing skills, and hardware ready to install CIITIX-WiFi

The PC which you will be installing CIITIX-WiFi on does not need to be a super spec machine, but if is being deployed as a mission critical assset you will be better off using new hardware or a virtual machine.

The installation hardware which was used for this tutorial was VMWare ESXi server, 1 vCPU, 1 vHDD (4gb), 768 Ram.

And just for trivia while sitting idle it is using 10Mhz and 7mb ram. Anything Pentium 3 based and up will suffice.

 

Let's get started

Burn your ISO onto CD and place that into your drive, and boot from the CD drive. Make sure you have no important data on the hard disk because the installation will destroy all existing data on the drive you install to.

1) After your system is booted you will see the following screen, at this point you choose 'Start GUI Install' and hit enter.

Using ATA Over Ethernet (AoE) On Ubuntu 10.04 (Initiator And Target)

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Last edited 08/13/2010

This guide explains how you can set up an AoE target and an AoE initiator (client), both running Ubuntu 10.04. AoE stands for "ATA over Ethernet" and is a storage area network (SAN) protocol which allows AoE initiators to use storage devices on the (remote) AoE target using normal ethernet cabling. "Remote" in this case means "inside the same LAN" because AoE is not routable outside a LAN (this is a major difference compared to iSCSI). To the AoE initiator, the remote storage looks like a normal, locally-attached hard drive.

I do not issue any guarantee that this will work for you!

 

1 Preliminary Note

I'm using two Ubuntu 10.04 servers here:

server1.example.com (Initiator): IP address 192.168.0.100 server2.example.com (Target): IP address 192.168.0.101

 

2 Loading The aoe Kernel Module On Both Systems server1/server2:

Before we start, we must make sure that the the kernel supports AoE:

grep ATA_OVER /boot/config-

Using iSCSI On Ubuntu 10.04 (Initiator And Target)

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Last edited 05/11/2009

This guide explains how you can set up an iSCSI target and an iSCSI initiator (client), both running Ubuntu 10.04. The iSCSI protocol is a storage area network (SAN) protocol which allows iSCSI initiators to use storage devices on the (remote) iSCSI target using normal ethernet cabling. To the iSCSI initiator, the remote storage looks like a normal, locally-attached hard drive.

I do not issue any guarantee that this will work for you!

 

1 Preliminary Note

I'm using two Ubuntu 10.04 servers here:

server1.example.com (Initiator): IP address 192.168.0.100 server2.example.com (Target): IP address 192.168.0.101

Because we will run all the steps from this tutorial with root privileges, we can either prepend all commands in this tutorial with the string sudo, or we become root right now by typing

sudo su

 

2 Setting Up The Target (server2)server2:

First we set up the target (server2):

aptitude install iscsitarget

Open /etc/default/iscsitarget...

vi /etc/default/iscsitarget

... and set ISCSITARGET_ENABLE to true:

ISCSITARGET_ENABLE

How To Set Up A Webgui Based Print Server On Ubuntu Server Using SWAT, CUPS, And SAMBA

Samba

This how-to describes the process of setting up an intranet based print server using Ubuntu server. By using CUPS SAMBA and SWAT the final product is a webgui based solution to a headless print server.

This How-to has been cobbled together from assorted other how-tos and forums by me after recording as best I could the method I used after googling the various problems I had along the way. It is primarily based on

http://ubuntuforums.org/showthread.php?t

Installing And Using OpenVZ On Ubuntu 10.04

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Last edited 08/18/2010

In this HowTo I will describe how to prepare an Ubuntu 10.04 server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license.

This howto is meant as a practical guide; it does not cover the theoretical backgrounds. They are treated in a lot of other documents in the web.

This document comes without warranty of any kind! I want to say that this is not the only way of setting up such a system. There are many ways of achieving this goal but this is the way I take. I do not issue any guarantee that this will work for you!

 

1 Preliminary Note

I'm using an x86_64 (amd64) system here. If you are on an i386 system, a few commands will be slightly different - I have added annotations to that parts.

 

2 Become root

Type

sudo su

to become root (or prepend all commands in this tutorial with the string sudo).

 

3 Change The Default Shell

/bin/sh is a symlink to /bin/dash, however we need /bin/bash, not /bin/dash. Therefore we do this:

dpkg-reconfigure dash

Install dash as /bin/sh? <-- No

 

 

4 Disable AppArmor

AppArmor is a security extension (similar to SELinux) that should provide extended security. In my opinion you don't need it to configure a secure system, and it usually causes more problems than advantages (think of it after you have done a week of trouble-shooting because some service wasn't working as expected, and then you find out that everything was ok, only AppArmor was causing the problem). Therefore I disable it.

We can disable it like this:

/etc/init.d/apparmor stop
update-rc.d -f apparmor remove
apt-get remove apparmor apparmor-utils

 

5 Installing OpenVZ

Unfortunately there are no OpenVZ packages in the official Ubuntu 10.04 repositories, therefore we have to build the OpenVZ kernel and the OpenVZ tools (vzctl, vzquota, vzpkg) ourselves.

First, run

uname -r

to find out your currently installed kernel version:

root