The Answer To The Media Access Control Question
Over the past few weeks I actually have acquired quite some emails approximately Ethernet playing cards, both wired and wi-fi, and more mainly, about Media Access Control (MAC) addresses. I think the main cause I’ve acquired so many questions about Ethernet cards and MAC addresses are human beings looking too relaxed their home wireless networks and their choice to apply MAC address filtering. This form of filtering in wi-fi networks can be configured to allow or deny precise computer systems to use or attach to the wi-fi community, based on the MAC cope with.
My first thought becomes to jot down an editorial just about MAC addresses and wireless Ethernet. After considering it I determined to amplify in this and go over some particular statistics approximately Ethernet playing cards and verbal exchange.
Different Ways Of Finding Your MAC Address And More
There are numerous methods of finding your Ethernet and communications protocol information. Many Ethernet card manufacturers have proprietary software that could display this records however they work differently depending on the producer. So we can use the Windows 2000 and XP “ipconfig” utility considering this is to be had in most of the people of Windows Operating Systems.
First, go to “begin” -> “run” and type “cmd” with out the quotes. Then hit the input key. At the command line kind “ipconfig /all”, once more with out the charges. Actually, simply typing ipconfig without the /all will paintings but will only offer you with abbreviated data regarding your community playing cards. An instance of what you might see through typing the “ipconfig /all” command is underneath with every item commented in green lettering:
Fault Tolerant And Highly Availability Computer Systems
There are numerous methods of finding your Ethernet and communications protocol facts. Many Ethernet card manufacturers have the proprietary software program that may display this fact but they work in a different way depending on the manufacturer. So we will use the Windows 2000 and XP “ipconfig” software in view that this is available in the majority of Windows Operating Systems.
First, visit “begin” -> “run” and type “cmd” with out the quotes. Then hit the enter key. At the command line type “ipconfig /all”, again with out the charges. Actually, just typing ipconfig without the /all will paintings but will only provide you with abbreviated information regarding your network playing cards. An instance of what you would possibly see through typing the “ipconfig /all” command is below:
OutPut Of The “Ipconfig /All” Command
Windows IP Configuration
Host Name . . . . . . . . . . . . : Home Computer
This is the name of your pc, usually described at some stage in the windows installation. However, it is able to be modified after set up.
Primary DNS Suffix . . . . . . . : area.Com
If your pc participates in a network consisting of a Microsoft Windows domain this item can also comprise the name of the domain.
Node Type . . . . . . . . . . . . : Unknown
The Node Type may additionally say Unknown, or peer-to-peer, or in a few cases “hybrid”. It is a setting that has to do with the Windows Internet Naming Services used in positive kinds of Windows area networks.
IP Routing Enabled. . . . . . . . : No
This putting determines if Windows XP or 2000 will function as an IP router. If you’ve got two or more network cards you could setup your device to behave as a router, forwarding communications requests from one network to any other. Windows 2000 can be configured to do this in a pretty straight forward style; Windows XP will want a registry amendment.
WINS Proxy Enabled. . . . . . . . : No
WINS Proxy is another setting that is related to the “Node Type” we discussed in advance. It is usually no longer a required placing in a domestic or small office network or newer forms of Microsoft Windows domains.
Ethernet adapter Wireless Network Connection 2:
If you have more than one Ethernet (community) cards for your structures, as I do on this computer, you may have a couple of listings. This one takes place to be the second Ethernet card, an internal wireless Ethernet card.
Description . . . . . . . . . . . : Broadcom 802.11b/g WLAN
This is the description of the Ethernet card, typically the Name / Manufacturer and type of Ethernet card. In this example, it’s miles a Broadcom wireless Ethernet card constructed into my computer.
Physical Address. . . . . . . . . : 00-ninety-4B-F1-6E-4A
And right here we’ve got the MAC deal with. The MAC cope with is a 48-bit hexadecimal code and is suppose to be a completely specific cope with. It is 48 bits due to the fact every quantity or letter in hexadecimal represents eight bits. Hexadecimal numbers range from 0,1,2,three,four,five,6,7,8,nine,A,B,C,D,E, F. There are 6 alpha-numeric codes therefore 6*eight=forty eight(bits). The first three codes pick out the producer of the card and the final codes are used to create a unique range. Theoretically, there should never be a card with same MAC cope with on a nearby network. However, there are a few exceptions. There is software program gear that permits you to change this code. In fact, that is a step a few hackers take to assault other structures on a nearby network. I say local community due to the fact MAC addresses aren’t routable between network segments. By spoofing this address, you could impersonate some other device on the nearby network. Traffic that turned into certain for the intended goal may be redirected to the hacker’s system. This is the cope with you’ll additionally use to populate a MAC address, or physical cope with desk while putting in place your wi-fi get admission to factor to assist MAC address filtering.
DHCP Enabled. . . . . . . . . . . : Yes
DHCP, or the Dynamic Host Control Protocol, if enabled way your computer systems IP deal with is being supplied with the aid of a DHCP server on your community. The DHCP server can be your wi-fi get right of entry to factor, cable/DSL router, cable modem, or a server to your community. Also, if a DHCP server isn’t always enabled for your network, your computers Operating System will automobile generate a random IP deal with inside a sure predefined variety. This method you may network a set of structures collectively while not having to manually assign the IP settings.
IP Address. . . . . . . . . . . . : 192.168.0.117
This parameter offers you with your current IP address. The deal with indexed above is what’s called a “private” deal with. There are certain instructions of IP addresses that have been set aside for private use. This approach on your inner, local, or non-public network at home or workplace. These addresses aren’t, or must no longer, be routable at the Internet. The Internet routes what are referred to as “legitimate” IP addresses. Your cable/DSL router or cable modem has a legitimate IP cope with assigned to its “outside” community interface. The external interface can be your telephone line or cable TV cable.
Subnet Mask . . . . . . . . . . . : 255.255.255.Zero
The Subnet Mask is a special wide variety, or in some felt, filter out, that breaks down your IP address, in this example non-public IP address, into sure agencies. IP addresses and Subnet Masks may be a complex count number and could take an entire article to move over.
Default Gateway . . . . . . . . . : 192.168.0.254
The default gateway, the IP addresses indexed above, is the IP address of the tool a good way to path your request, along with while you try to browse an internet site, to the Internet. It is a bit extra complicated than that even though as gateways or routers can direction site visitors to numerous special networks, even other private networks. At your property or small workplace, this gateway most possibly is your cable/dsl modem or router.
DHCP Server . . . . . . . . . . . : 192.168.Zero.49
The DHCP server, bear in mind we talked a bit about this above, is the device that assigns your pc an IP address and other information. DHCP servers can assign all forms of facts consisting of; Default Gateway, Domain Name Servers (DNS), IP address, Subnet Mask, Time Server, and lots extra.
DNS Servers . . . . . . . . . . . : 192.168.0.Forty-nine, sixty four.105.197.58
DNS Servers are internal or external servers that resolve Fully Qualified Domain Names (FQDN), which includes two IP addresses. This is done due to the fact computer systems don’t sincerely transmit your requests the usage of the area call, they use the IP cope with assigned to the FQDN. For most domestic or small workplace customers, the number one DNS server is the IP cope with of your cable/dsl router. Your cable/dsl router then queries an outside DNS server at the Internet to carry out the actual decision of the FQDN to IP address. The cope with 192.168.0.Forty-nine is an inner personal tool on my network while the sixty-four.One hundred and five.197.58 is an external public Internet DNS server and is gift simply in case my router has trouble acting the DNS decision obligations.
Lease Obtained. . . . . . . . . . : Sunday, March 19, 2006, 6:38:16 PM
These statistics tell you whilst your computer acquired its IP deal with and other statistics from a DHCP server. You will be aware it says “Lease Obtained”, that is because most DHCP servers handiest lease the IP address to you from a pool of to be had the deal with. For example, your pool may be 192.168.1.1 via 192.168.1.50. So your DHCP server has 50 IP addresses to select from when assigning your computer its IP address.
Lease Expires . . . . . . . . . . : Wednesday, March 29, 2006, 9:38:16 PM
When the IP address, assigned by way of the DHCP server, lease expires it’s going to attempt to lease you the equal or another IP deal with. This feature can typically be modified by the DHCP server. For instance, on some fully practical DHCP servers, you could configure the Lease to in no way expire or to expire within 1 day and so on.
Why Are MAC Addresses So Important And How Do They Work
To bounce again to MAC address for simply a piece. You might imagine that IP addresses are the most vital factor with regards to network communication. The fact is, MAC addresses are very important due to the fact without them computer systems could not be capable of speak over Ethernet networks. When a computer wants to speak with any other laptop on a local community, it’ll make a printed request, or ask a question, of who owns a particular IP address. For example, your computer may additionally say “Who is 192.168.0.254”. Using the records above, my default gateway is 192.168.Zero.254 and could solution “I am “00-90-4B-F1-6E-4A” 192.168.Zero.254″. It sends returned its MAC deal with. That MAC address then goes into what is referred to as an Address Resolution Protocol (ARP) table on your laptop. You can see this fact by way of going to the command spark off like you did above and typing “are -a”. You get statistics like the following:
Internet Address Physical Address Type
192.168.0.Forty nine 00-12-17-5c-a2-27 dynamic
192.168.Zero.109 00-12-17-5c-a2-27 dynamic
192.168.0.112 00-0c-76-93-94-b2 dynamic
192.168.0.254 00-0e-2e-2e-15-61 dynamic
How A Hacker Can Use MAC Addresses In An Attack
You will notice the IP addresses and to the right of them the MAC addresses. Without this records, with out the MAC cope with, you would not be studying this text right now. MAC addresses aren’t routable like IP addresses. The paintings on your nearby or private community. However, devices at the Internet carry out the equal duties. Routers and switches keep a list in their peer devices MAC address just like your computers and gadgets on your private home or workplace community. I referred to above that MAC addresses can be changed in order to redirect requests. For example, if I had been in your workplace network and also you had an inner web server that took non-public data as input, I may want to tell your pc to go to my pc for the net web site with the aid of broadcasting my MAC address tied to the actual web servers IP address. I would do that when you pc asked “Who is the “Real Web Server”. I may want to setup a fake internet server that looks much like the actual element and begins accumulating facts the actual web server could commonly acquire. You can see how dangerous this could be.
There are several other smooth ways you could find your MAC address but they can be a bit difficult if you have multiple internal network card. Most outside USB or PCMCIA stressed out and wireless Ethernet cards have their MAC cope with printed on them. In cases where the stressed out or wi-fi network card is inside your laptop, together with in laptops, the MAC cope with is every now and then revealed on the lowest of the laptop. Even Desktop systems cards which might be inserted in PCI slots have the MAC cope with printed on the Ethernet card.
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