Arindam Bhadra: CCTV budget

Showing posts with label CCTV budget. Show all posts

Sunday, February 26, 2012

The Inner Workings Of CCTV Cameras

With the advancement in technology criminal procedures have also become more advanced. This is why the use of CCTV as a means of security surveillance has increased in recent years. CCTV cameras are used for spy and surveillance purposes. These stealth cameras are sometimes disguised whereas at other times they are placed in obvious locations to ward of the security threat. Nonetheless it is the highly advanced low light monochrome camera that provides the ideal security back up.

Some facts about the CCTV cameras

The CCTV sends out video signals that are directly encoded and fed to a 110 volt power line. You will find all kinds of CCTV cameras out there to come with a companion decoder. This device can plugged anywhere including an ordinary television set at your home. CCTV cameras make use of line level RCA type cables which are the standard cables for all kinds of video output. One of the most advantageous facts about CCTV cameras is the use of infrared technology. This advanced technology gives CCTV cameras the ability to pick up crystal clear video images even in total darkness. The best of CCTV cameras will be able to pick up images in pitch dark up to a distance of thirty feet.

One of the things that have led to the widespread use of CCTV cameras is their durability. You will be able to find CCTV cameras that have the ability to operate when situated at a distance of up to two thousand feet from AC wiring. CCTV cameras will also be able to deliver you top quality picture even when the power lines are loaded with other heavy electronics. Another plus point of the CCTV camera collection is its ability to capture images in an incredible wide angle view.

The technology embedded in CCTV cameras enables them to pick up even the slightest of changes. They are highly sensitive and will be able to deliver you clear images even in total darkness. Some CCTV cameras give you the ability to increase their infrared capability by adding supplemental infrared floodlights.

CCTV cameras are incredibly versatile when it comes to their usability. The fact that you can directly record the captured image onto your home VCR makes it very convenient. Plus the fact that you can use your very own TV set for monitoring purposes.

The latest releases in CCTV cameras provide the ultimate security solutions for home owners and business enterprises alike. Interested individuals can take advantage of the easy availability of CCTV cameras through the internet. There is a plethora of choices for those seeking CCTV cameras with the different models having varying features. You can check to see which CCTV camera meets your requirements and pick up a bargain deal using the internet. Rest assured you will be able to find one that meets your requirements and fits your budget.

Saturday, June 4, 2011

How do I setup IP forwarding/filtering with the Connect WAN

Introduction

The WAN supports four features which provide security and IP traffic forwarding when using incoming or Mobile Terminated connections:

1. Network Address Translation (NAT)

2. Generic Routing Encapsulation (GRE) forwarding

3. TCP/UDP port forwarding

4. IP Filtering

This document describes each function, how they are used in conjunction with each other, how they are used, and what issues can occur with each if not used properly.

Network Address Translation (NAT)

NAT allows the Connect WAN to have a single public IP address on the mobile link, while allowing multiple private IP addressed devices connected to the Ethernet interface.

Outgoing traffic (mobile initiated) from the private network to the public mobile network assumes the IP address of the public mobile interface. An internal table tracks which internal IP address made the outgoing request so that responses get sent to the proper requestor.

For example, a workstation at IP address 192.168.1.15 sends a request to www.arindamcctvaccesscontrol.blogspot.com. The source IP address is changed by the Connect WAN address translation to the public

Incoming (mobile terminated) traffic is either designated to the Connect WAN itself (i.e. HTTP or telnet connections for configuration or monitoring), or is forwarded to hosts via the Ethernet interface based either on GRE or TCP/UDP port forwarding which is covered below.

NAT provides two main benefits:

1. Security: NAT hides the Private IP addresses of the devices on the Connect WAN''''s Ethernet network.

2. IP Address Availability: IP addresses are in short supply and cost money. The Connect WAN need be provided only one IP address from the wireless carrier.

NAT is enabled by default on the Connect WAN. It should not be disabled unless there is a specific reason to do so.

Generic Routing Encapsulation (GRE) forwarding

GRE is a transport layer protocol, designated as IP protocol number 47, is used by many routers, WAN switches and VPN concentrators, to effectively tunnel traffic over a WAN between routers. Note that GRE itself provides no encryption but protocols such as PPTP can use GRE. IPSec can be encapsulated in GRE (and vice-versa). GRE uses IP-in-IP and allows private IP addresses to be tunneled through a public network.

The Connect WAN provides a simple checkbox to turn on GRE forwarding to pass GRE traffic from the mobile interface through to a router on the Ethernet interface. Note the Connect WAN only passes GRE traffic and does not terminate it.

Here is an example diagram:

Figure 1 - GRE Forwarding

The HQ router''s peer GRE address is the mobile IP address of the Connect WAN, which in this case is 166.213.229.218. The Connect WAN has GRE forwarding enabled and will send to the router''s Ethernet WAN port, in this case 192.168.1.2. Typically this connection is a directly connected Ethernet cable.

An example similar to the above is where GRE tunneling is used to create a backup WAN connection to a primary Frame Relay connection through the Connect WAN and wireless network.

TCP/UDP Port Forwarding

Normally, traffic initiated from a host site to a Connect WAN is blocked by NAT, unless the traffic is destined for the Connect WAN itself. Port forwarding provides a means to pass traffic from the mobile interface to devices connected to the Connect WAN''''s Ethernet port. There are two main applications where port forwarding is required:

1. Pass application data traffic, such as polls or requests, to Ethernet connected devices, and

2. Pass VPN traffic, such as IPSec-in-UDP, through to routers or VPN appliances.

For example, three devices are attached to the Connect WAN''''s Ethernet port:

Figure 2 - TCP Port Forwarding

The application uses a protocol that polls the devices using the device IP address and TCP port 502 (which is Modbus). On local LANs and publicly routable IP addresses this is not a problem.

NAT hides the private Ethernet IP addresses of the devices connected behind the Connect WAN''''s Ethernet port. The application can then only send polls to one IP address the mobile IP in this case 166.213.229.218.

TCP port forwarding is used to forward the IP polls to one or more devices on the Connect WAN Ethernet port. Different TCP port numbers are used to designate which device gets the proper traffic. The application must be able to support changing the TCP protocol port number from the default of 502. In this case the application is configured to poll according to this table:

Remote Device	Destination IP Address	Destination TCP Port
One	163.213.229.218	12001
Two	163.213.229.218	12002
Three	163.213.229.218	12003

Notice the destination IP address is the Connect WAN''''s mobile IP address.

The Connect WAN is configured with a TCP/UDP forwarding table as follows:

Source TCP Port	Destination IP Address	Destination TCP Port
12001	192.168.1.2	502
12002	192.168.1.3	502
12003	192.168.1.4	502

Incoming traffic is then routed to the proper device. The devices can use their standard TCP port of 502.

The main issue with port forwarding in this case is when the polling application does NOT allow the user to specify the TCP or UDP port used. The workaround is to use routers that support GRE, VPN, or other forms of tunneling that can be forwarded through the Connect WAN.

Another example of port forwarding is forwarding of IPSec-in-UDP traffic to a VPN appliance or router attached to the Connect WAN''''s Ethernet port. Figure 1 above shows a GRE tunnel. In much the same way, IPSec traffic can be encapsulated in UDP to prevent NAT from modifying the IPSec headers (which would invalidate the traffic). IPSec-in-UDP implementations always use UDP port 500 for IKE/ISAKMP, but can use various UDP port numbers for the AH/ESP traffic. Here is an example of UDP port forwarding entries on a Connect WAN for IPSec in UDP:

Protocol	Source Port	Destination IP Address	Destination Port
UDP	500	192.168.1.2	500
UDP	4500	192.168.1.2	4500

IP Filtering

IP Filtering is a security feature that allows the user to block all incoming, mobile terminated traffic into the Connect WAN except for traffic from specific IP addresses and/or subnets. There are three IP Filtering settings on the Connect WAN:

1. Only allow access from the following devices and networks. When checked this blocks ALL incoming traffic except for the traffic from the IP address/subnets listed in the "allow access" tables.

2. Automatically allow access from all devices on the local subnet. This allows out-bound traffic from the private Ethernet network out to the mobile network and beyond.

3. Allow access from the following devices and/or subnets. When the "Only allow access from the following devices and networks" box is checked, you must provide entries here to allow in-coming mobile traffic to be passed through the Connect WAN.

CAUTION: Incorrect settings here can stop some or all traffic. For example, checking "Only allow access from the following devices and networks" without adding IP addresses or subnets to the "allow access" tables will block ALL incoming traffic, even responses from outgoing requests.