Difference between Dynamic and Static IP

Difference between Dynamic and Static IP

The major difference between dynamic and static IP is that dynamic IPs change every time one connects to the internet, while static IPs remain the same.

Internet Protocols, also known as IP addresses is a 32-bit number that is usually assigned to a computer when it connected to a network, such as the Internet. The IP address works similar to an actual address and lets computers know where to send data packets. The network devices use these address in order to communicate with each other.

The IP address are made up of 4 parts of numbers that are divided by dots (.) So, a typical IP address will looking something like – 72.169.189.01.

Although, the IP Based product / computers communicate with each other using IP addresses, to make it easier to remember the internet uses DNS or Domain Name System. This DNS is sort of an address book that pairs names to IP addresses. For example, if one wanted to visit the Google website, they would type in www.google.com in the address bar. The DNS will look up the IP address (74.125.239.35) paired with this name and will ping that address. Their system will respond back and the webpage will load on your computer.

There are two types of IPs – dynamic and static IP addresses. The major difference between dynamic and static IP is that dynamic IPs change every time one connects to the internet, while static IPs remain the same.

There are limited amount of IP addresses that are available and for this reason, many companies assign dynamic IPs, unless a static IP is asked for. So, every time a device is connected to the Internet, the IP address can change. This also allows the limited number of IPs to become reused, making it more convenient.

Broadband connections today lease IP addresses and use the DCHP dynamic IP address system. This system is also often considered safer, since the IP is always changing it makes it more difficult to hack the computer. Static IPs are commonly used by companies or people who require a similar IP address. The can apply for a static IP by paying a fee.

Comparison between Dynamic and Static IP:

	Dynamic IP	Static IP
Full form	Dynamic Internet Protocol	Static Internet Protocol
Definition	The internet protocol will constantly change	The internet protocol will remain the same
Cost Effective	More cost effective	Less cost effective
Security Risk	Lower	Higher
Upload/Download Speed	Slower	Faster
Good for	Good for residential user and small business owners	Web servers, email servers and other Internet servers. Also, for VOIP, VPN, playing online games or game hosting

Configure Router as Switch

How to configure router as switch?
Most likely you will ask this question if you plan to expand you home network, and you have only extra Ethernet router but not switch. At the same time you try to make use this extra router if possible without paying more on extra switch. Well… It’s pretty simple to get it done, keep on reading.

As you can see from 2 examples below, we can use second Ethernet router to expand existing wireless network or Ethernet home network, so that you can connect more computers to your network. Please note that first and second routers must be located on same network, because the second router just acts as a switch, not router anymore.

Ok. Let’s start to configure second router as switch.

1) Connect first router’s LAN port to second router’s LAN port by using a crossover cable. If one of the routers supports auto MDI/MDI-X feature, you can use either straight or crossover cable. Remember, don’t make any connection to second router’s WAN or Internet port.

2) Ok. Now assuming your first router's LAN IP is 192.168.1.1 with subnet mask 255.255.255.0, and then this will act as gateway for entire network (including the computers that connect to second router). If you would like to enable DHCP, then just enable the DHCP setting on first router and it will act as DHCP server for entire network (you don't need to enable DHCP on second router anymore). As an example, you can enable DHCP with IP range 192.168.1.2-250, subnet mask 255.255.255.0, gateway 192.168.1.1, DNS servers 208.67.222.222 and 208.67.220.220 on first router.

3) After talking about first router's configuration, proceed to log on to second router’s configuration page, then give this router an IP by configuring an IP and subnet mask under LAN setting. The IP that you configure should be located on subnet same with first router's subnet and this IP is not being used by any other device. If you have configured first router’s LAN IP and DHCP setting as shown in step 2 above, you can easily configure second router with LAN IP 192.168.1.251, 192.168.1.252 or 192.168.1.253 and subnet mask 255.255.255.0.

4) After that, don’t enable DHCP or any other settings on second router. If you have enabled DHCP or other settings, disable them. Finally SAVE all the settings. And now your have completed your mission of making second router as switch.

5) If you have computer that is configured to obtain IP automatically, connect it to other LAN port of this new "network switch", then it should be able connect to network, ping router IP and access to internet.

How Domain Name System (DNS) Works

In the world of Internet and the area of computer networks, you will often come across the term Domain Name System or Domain Name Service which is simply referred to as DNS. The working of DNS forms one of the basic concepts of computer networks whose understanding is very much essential especially if you are planning to get into the field of ethical hacking or network security.

In this post, I will try to explain how Domain Name System works in a very simple and easy to follow manner so that even the readers who do not have any prior knowledge of computer networks should be able to understand the concept.

What is a Domain Name System?

A “Domain Name System” or “Domain Name Service” is a computer network protocol whose job is to map a user friendly domain name such as “arindamcctvaccesscontrol.blogspot.com” to its corresponding IP address like “173.245.61.120″.

Every computer on the Internet, be it a web server, home computer or any other network device has a unique IP address allotted to it. This IP address is used to establish connections between the server and the client in order to initiate the transfer of data. Whether you are trying to access a website or sending an email, the DNS plays a very important role here.

For example, when you type “www.google.com” on your browser’s address bar, your computer will make use of the DNS server to fetch the IP address of Google’s server that is “74.125.236.37″. After obtaining the IP address, your computer will then establish a connection with the server only after which you see the Google’s home page loading on your browser. The whole process is called DNS Resolution.

With millions of websites on the Internet, it is impossible for people to remember the IP address of every website in order to access it. Therefore, the concept of domain name was introduced so that every website can be identified by its unique name which makes it easy for people to remember. However, the IP address is still used as the base for internal communication by network devices. This is where the DNS comes in to action that works by resolving the user friendly domain name to its corresponding machine friendly IP address.

In simple words, domain names are for humans while IP addresses are for network devices. The “Domain Name System” is a protocol to establish a link between the two. Hence, it is not a surprise that you can even load a website by directly typing its IP address instead of the domain name in the browser’s address bar (give it a try)!

Types of DNS Servers and their Role:

The Domain Name System (DNS) is a distributed database that resides on multiple computers on the Internet in a hierarchical manner. They include the following types:

Root Name Servers:

The root servers represent the top level of the DNS hierarchy. These are the DNS servers that contain the complete database of domain names and their corresponding IP addresses. Currently, there are 13 root servers distributed globally which are named using the letters A,B,C and so on up to M.

Local Name Servers:

Local servers represent the most lower level DNS servers that are owned and maintained by many business organizations and Internet Service providers (ISPs). These local servers are able to resolve frequently used domain names into their corresponding IP addresses by caching the recent information. This cache is updated and refreshed on a regular basis.

How DNS Server Works?

Whenever you type a URL such as “http://www.google.com” on your browser’s address bar, your computer will send a request to the local name server to resolve the domain name into its corresponding IP address. This request is often referred to as a DNS query. The local name server will receive the query to find out whether it contains the matching name and IP address in its database. If found, the corresponding IP address (response) is returned. If not, the query is automatically passed on to another server that is in the next higher level of DNS hierarchy. This process continues until the query reaches the server that contains the matching name and IP address. The IP address (response) then flows back the chain in the reverse order to your computer.

In rare cases where none of the lower level DNS servers contain the record for a given domain name, the DNS query eventually reaches one of the root name server to obtain the response.

FAQs about Domain Name System:

Here is a list of some of the FAQs about DNS:

How does a “root name server” obtain the information about new domains?

Whenever a new domain name is created or an existing one is updated, it is the responsibility of the domain registrar to publish the details and register it with the root name server. Only after this, the information can move down the DNS hierarchy and get updated on the lower level DNS servers.

What is DNS propagation?

Whenever a new domain name is registered or an existing one is updated, the information about the domain must get updated on all the major DNS servers so that the domain can be reached from all parts of the globe. This is called DNS propagation and the whole process can take anywhere from 24 to 72 hours to get completed.

How often the DNS servers are updated to refresh the cache?

There is no specific rule that defines the rate at which DNS servers should be updated. It usually depends on the organization such as the ISP that maintains the server. Most DNS servers are updated on an hourly basis while some may update their databases on a daily basis.

I hope you have now understood the working of DNS in a very convincing manner. Pass your comments and share your opinion.

TCP VS UDP & IP Topics

Can you explain the difference between UDP and TCP internet protocol (IP) traffic and its usage with an example?
A. Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)is a transportation protocol that is one of the core protocols of the Internet protocol suite. Both TCP and UDP work at transport layer TCP/IP model and both have very different usage.

Difference between TCP and UDP

TCP	UDP
Reliability: TCP is connection-oriented protocol. When a file or message send it will get delivered unless connections fails. If connection lost, the server will request the lost part. There is no corruption while transferring a message.	Reliability: UDP is connectionless protocol. When you a send a data or message, you don't know if it'll get there, it could get lost on the way. There may be corruption while transferring a message.
Ordered: If you send two messages along a connection, one after the other, you know the first message will get there first. You don't have to worry about data arriving in the wrong order.	Ordered: If you send two messages out, you don't know what order they'll arrive in i.e. no ordered
Heavyweight: - when the low level parts of the TCP "stream" arrive in the wrong order, resend requests have to be sent, and all the out of sequence parts have to be put back together, so requires a bit of work to piece together.	Lightweight: No ordering of messages, no tracking connections, etc. It's just fire and forget! This means it's a lot quicker, and the network card / OS have to do very little work to translate the data back from the packets.
Streaming: Data is read as a "stream," with nothing distinguishing where one packet ends and another begins. There may be multiple packets per read call.	Datagrams: Packets are sent individually and are guaranteed to be whole if they arrive. One packet per one read call.
Examples: World Wide Web (Apache TCP port 80), e-mail (SMTP TCP port 25 Postfix MTA), File Transfer Protocol (FTP port 21) and Secure Shell (OpenSSH port 22) etc.	Examples: Domain Name System (DNS UDP port 53), streaming media applications such as IPTV or movies, Voice over IP (VoIP), Trivial File Transfer Protocol (TFTP) and online multiplayer games etc

Further readings

UDP is the faster protocol as it doesn't wait for acknowledgement so it is not at all having reliability as  compared to TCP.

Bridging the Analog-IP Gap

The name "encoder" does not really do these technological miracles justice. These investment-protecting, budget-saving marvels build a bridge between two generations of surveillance technology and bring harmony to your network.

IP-based video surveillance systems bring many important benefits. The image quality they deliver is a vast improvement. The networks are more scalable and cheaper to run. Better still, computerization means you can automate systems to bring about event management and intelligent video. Nevertheless, it is too early to claim that this development has rendered analog CCTV surveillance systems obsolete.

One option to installers would be to replace everything analog. This would mean getting rid of the existing analog cameras, the coaxial cables that have been laid inside and outside the buildings, the recording systems (AVRs or DVRs) and the management system. It would then be necessary to introduce an entirely new Ethernet cabling infrastructure, which would involve not insubstantial disruption, along with new IP-compatible storage hardware and a management system suited to IP or network video.

In many cases, that would be a waste of time and money, and the people who bought analog systems are not going to write off their investment any time soon, especially when around 95 percent of the estimated 40 million surveillance cameras installed in the world are still analog.

While analog technology is being fast eclipsed by IP video, which is growing at 30 percent a year according to IMS Research, there is no reason why the two infrastructures cannot be rationalized together, apart from a few technological hurdles. These barriers to integration are, in most cases, easily surmountable.

For most installations, the most valuable service you can offer your clients is to migrate them from analog to IP video by making judicious use of their existing network. The key to this magic passage is the video encoder. Encoders help convert analog networks into IP-friendly formats, putting the existing investment in cameras and coaxial cable to good use.