Ethernet Pci Card

Different Ways of Finding Your MAC Address on Wired & Wireless Network Cards

The Answer To The Media Access Control Question
----------------------------
Over the past few weeks I have received quite a few e-mails about Ethernet cards, both wired and wireless, and more specifically, about Media Access Control (MAC) addresses. I think the main reason I’ve received so many questions about Ethernet cards and MAC addresses is people trying to secure their home wireless networks and their desire to use MAC address filtering. This type of filtering in wireless networks can be configured to allow or deny specific computers to use or attach to the wireless network, based on the MAC address.

My first thought was to write an article just about MAC addresses and wireless Ethernet. After thinking about it I decided to expand on this and go over some specific information about Ethernet cards and communication.

Different Ways of Finding Your MAC Address and More
--------------------------------------------------
There are several ways of finding your Ethernet and communications protocol information. Many Ethernet card manufacturer’s have proprietary software that can reveal this information but they work differently depending on the manufacturer. So we will use the Windows 2000 and XP “ipconfig” utility since this is available in the majority of Windows Operating Systems.

First, go to “start” -> “run” and type “cmd” without the quotes. Then hit the enter key. At the command line type “ipconfig /all”, again without the quotes. Actually, just typing ipconfig without the /all will work but will only provide you with abbreviated information regarding your network cards. An example of what you might see by typing the “ipconfig /all” command is below with each item commented in green lettering:

Fault Tolerant And Highly Availability Computer Systems
----------------------------
There are several ways of finding your Ethernet and communications protocol information. Many Ethernet card manufacturer’s have proprietary software that can reveal this information but they work differently depending on the manufacturer. So we will use the Windows 2000 and XP “ipconfig” utility since this is available in the majority of Windows Operating Systems.

First, go to “start” -> “run” and type “cmd” without the quotes. Then hit the enter key. At the command line type “ipconfig /all”, again without the quotes. Actually, just typing ipconfig without the /all will work but will only provide you with abbreviated information regarding your network cards. An example of what you might see by 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 computer, typically defined during the windows installation. However, it can be changed after installation.

Primary Dns Suffix . . . . . . . : domain.com
If your computer participates in a network such as a Microsoft Windows domain this item may contain the name of the domain.

Node Type . . . . . . . . . . . . : Unknown
The Node Type may say Unknown, or peer-to-peer, or in some cases “hybrid”. It is a setting that has to do with the Windows Internet Naming Services used in certain types of Windows domain networks.

IP Routing Enabled. . . . . . . . : No
This setting determines if Windows XP or 2000 will function as an IP router. If you have two or more network cards you can setup your system to act as a router, forwarding communications requests from one network to another. Windows 2000 can be configured to do this in a pretty straight forward fashion; Windows XP will need a registry modification.

WINS Proxy Enabled. . . . . . . . : No
WINS Proxy is another setting that is related to the “Node Type” we discussed earlier. It is normally not a required setting in a home or small office network, or newer types of Microsoft Windows domains.

Ethernet adapter Wireless Network Connection 2:
If you have multiple Ethernet (network) cards in your systems, as I do in this laptop, you will have multiple listings. This one happens 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, usually the Name / Manufacturer and type of Ethernet card. In this case, it is a Broadcom wireless Ethernet card built into my laptop.

Physical Address. . . . . . . . . : 00-90-4B-F1-6E-4A
And here we have the MAC address. The MAC address is a 48 bit hexadecimal code and is suppose to be a totally unique address. It is 48 bits because each number or letter in hexadecimal represents 8 bits. Hexadecimal numbers range from 0,1,2,3,4,5,6,7,8,9,A, B, C, D, E, F. There are 6 alphanumeric codes hence 6*8=48(bits). The first 3 codes identify the manufacturer of the card and the remaining codes are used to create a unique number. Theoretically there should never be a card with same MAC address on a local network. However, there are a few exceptions. There are software tools that allow you to change this code. In fact, this is a step some hackers take to attack other systems on a local network. I say local network because MAC addresses are not routable between network segments. By spoofing this address, you can impersonate another machine on the local network. Traffic that was bound for the intended target can be redirected to the hacker’s machine. This is the address you would also use to populate a MAC address, or physical address table when setting up your wireless access point to support MAC address filtering.

DHCP Enabled. . . . . . . . . . . : Yes
DHCP, or the Dynamic Host Control Protocol, if enabled means your computers IP address is being provided by a DHCP server on you network. The DHCP server could be your wireless access point, cable/dsl router, cable modem, or a server on your network. Also, if a DHCP server is not enabled on your network, your computers Operating System will auto generate a random IP address within a certain predefined range. This means you could network a group of systems together without having to manually assign the IP settings.

IP Address. . . . . . . . . . . . : 192.168.0.117
This parameter provides you with your current IP address. The address listed above is what is called a "private" address. There are certain classes of IP addresses that have been set aside for private use. This means for your internal, local, or private network at home or office. These addresses are not, or should not, be routable on the Internet. The Internet routes what are called “valid” IP addresses. Your cable/dsl router or cable modem has a valid IP address assigned to its “external” network interface. The external interface may be your phone line or cable TV cable.

Subnet Mask . . . . . . . . . . . : 255.255.255.0
The Subnet Mask is a special number, or in some sense, filter, that breaks down your IP address, in this case private IP address, into certain groups. IP addresses and Subnet Masks can be a complicated matter and would take an entire article to go over.

Default Gateway . . . . . . . . . : 192.168.0.254
The default gateway, the IP addresses listed above, is the IP address of the device that will route your request, such as when you try to browse a website, to the Internet. It is a bit more complicated than that though as gateways or routers can route traffic to various different networks, even other private networks. At your home or small office, this gateway most likely is your cable/dsl modem or router.

DHCP Server . . . . . . . . . . . : 192.168.0.49
The DHCP server, remember we talked a little about this above, is the device that assigns your computer an IP address and other information. DHCP servers can assign all kinds of information such as; Default Gateway, Domain Name Servers (DNS), IP address, Subnet Mask, Time Server, and much more.

DNS Servers . . . . . . . . . . . : 192.168.0.49, 64.105.197.58
DNS Servers are internal or external servers that resolve Fully Qualified Domain Names (FQDN), to IP addresses. This is done because computers don’t actually transmit your requests using the domain name, they use the IP address assigned to the FQDN. For most home or small office users, the primary DNS server is the IP address of your cable/dsl router. Your cable/dsl router than queries an external DNS server on the Internet to perform the actual resolution of the FQDN to IP address. The address 192.168.0.49 is an internal private device on my network whereas the 64.105.197.58 is an external public Internet DNS server and is present just in case my router has trouble performing the DNS resolution tasks.

Lease Obtained . . . . . . . . . .: Sunday, March 19, 2006 6:38:16 PM
This information tells you when your computer received its IP address and other information from a DHCP server. You will notice it says “Lease Obtained”, that is because most DHCP servers only lease the IP address to you from a pool of available address. For instance, your pool may be 192.168.1.1 through 192.168.1.50. So your DHCP server has 50 IP addresses to choose from when assigning your computer its IP address.

Lease Expires . . . . . . . . . . : Wednesday, March 29, 2006 9:38:16 PM
When the IP address, assigned by the DHCP server, lease expires it will attempt to lease you the same or another IP address. This function can typically be changed on the DHCP server. For instance, on some fully functional DHCP servers, you can configure the Lease to never expire, or to expire within 1 day and so on.

Why Are MAC Addresses So Important And How Do They Work
------------------------------------------------------
To jump back to MAC address for just a bit. You may think that IP addresses are the most important thing when it comes to network communication. The reality is, MAC addresses are very important because without them computers would not be able to communicate over Ethernet networks. When a computer wants to speak with another computer on a local network, it will make a broadcast request, or ask a question, of who owns a particular IP address. For instance, your computer may say “Who is 192.168.0.254”. Using the information above, my default gateway is 192.168.0.254 and will answer “I am “00-90-4B-F1-6E-4A” 192.168.0.254”. It sends back its MAC address. That MAC address then goes into what is called a Address Resolution Protocol (ARP) table on your computer. You can see this information by going to the command prompt like you did above and typing "arp –a". You will get information like the following:

Internet Address Physical Address Type
192.168.0.49 00-12-17-5c-a2-27 dynamic
192.168.0.109 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 information, without the MAC address, you would not be reading this article right now. MAC addresses are not routable like IP addresses. They work on your local or private network. However, devices on the Internet perform the same tasks. Routers and switches maintain a list of their peer device MAC address just like your computers and devices on your home or office network. I mentioned above that MAC addresses can be changed in order to redirect requests. For instance, if I were on your office network and you had an internal web server that took personal information as input, I could tell your computer to go to my laptop for the web site by broadcasting my MAC address tied to the real web servers IP address. I would do this when you computer asked “Who is the “Real Web Server””. I could setup a fake web server that looks just like the real thing, and start collecting information the real web server would normally collect. You can see how dangerous this can be.

Conclusion
-----------
There are several other easy ways you can find your MAC address but they can be a little confusing if you have more than one internal network card. Most external USB or PCMCIA wired and wireless Ethernet cards have their MAC address printed on them. In cases where the wired or wireless network card is inside your computer, such as in laptops, the MAC address is sometimes printed on the bottom of the laptop. Even Desktop systems cards that are inserted in PCI slots have the MAC address printed on the Ethernet card.

About the Author

Did you find this article useful? For more useful tips and hints, points to ponder and keep in mind, techniques, and insights pertaining to Internet Business, do please browse for more information at our websites.

GIGABIT PCI EXPRESS ETHERNET CARD $16.99 GIGABIT PCI EXPRESS ETHERNET CARD

IC Intracom / FAST ETHERNET PCI CARD / 509510 $24.66 IC Intracom - FAST ETHERNET PCI CARD - 509510

Compaq Ethernet 10/100Mpbs PCI Network Card 118042001 $33.5 Compaq Ethernet 10/100Mpbs PCI Network Card 118042001

Intel E1G44ET2 Gigabit Ethernet Card - PCI Express $471.37 Intel E1G44ET2 Gigabit Ethernet Card - PCI Express

Netgear RN12P2GE Gigabit Ethernet Card - PCI RN12P2GE100WWS $273.53 Netgear RN12P2GE Gigabit Ethernet Card - PCI RN12P2GE100WWS

Plug-In Card - Pci Express - 10 Gigabit Ethernet $782.99 PLUG-IN CARD - PCI EXPRESS - 10 GIGABIT ETHERNET

IBM Ethernet Card 10/100 PCI Card 9406 21H5460 $65 IBM Ethernet Card 10/100 PCI Card 9406 21H5460

1G Gigabit 1000MB Ethernet LAN to PCI-E Express Card Adapter $11.99 PCI-e PCI-Express Gigabit Ethernet LAN Network Card

NEW! 10/100M PCI RJ45 Ethernet NIC Network Lan Adaptor Card $22.49 Brand NEW 10/100MB PCI Ethernet/Network NIC/LAN Card

Netgear / Netgear RN12P2GE Gigabit Ethernet Card - PCI / RN12P2GE-100WWS $279 Netgear - Netgear RN12P2GE Gigabit Ethernet Card - PCI - RN12P2GE-100WWS

Startech.com / StarTech.com Fiber Optic Gigabit Ethernet PCI Express Card / PEX1000MMSC $167.09 Startech.com - StarTech.com Fiber Optic Gigabit Ethernet PCI Express Card - PEX1000MMSC

Znyx Networks 4-Ports Fast Ethernet Card PCI ZX436Q $348.98 Znyx Networks 4-Ports Fast Ethernet Card PCI ZX436Q

Dell Pro Ethernet 1000Gbps 2-Ports PCI-E Network Card X3959 $73.68 Dell Pro Ethernet 1000Gbps 2-Ports PCI-E Network Card X3959

Dell Ethernet 1000T Dual Port PCI Card 6Y500 $65 Dell Ethernet 1000T Dual Port PCI Card 6Y500

Mellanox ConnectX-3 10Gigabit Ethernet Card - PCI Express x8 - Internal MCX354AQCBT $960.35 Mellanox ConnectX-3 10Gigabit Ethernet Card - PCI Express x8 - Internal MCX354AQCBT

HP G2 Dual Port 10Gigabit Ethernet Card PCI-E 518001001 $576.36 HP G2 Dual Port 10Gigabit Ethernet Card PCI-E 518001001

TRENDNET 32-bit PCI 10/100Mbps NWay Fast Ethernet Card TE100PCIWN $13.93 TRENDNET 32-bit PCI 10/100Mbps NWay Fast Ethernet Card TE100PCIWN

QLogic QLE3044 GigaBit Ethernet Card PCI Express QLE3044RJCK $237.1 QLogic QLE3044 GigaBit Ethernet Card PCI Express QLE3044RJCK

Intel I340 GigaBit Ethernet Card PCI Express x4 E1G44HTBLK $287.8 Intel I340 GigaBit Ethernet Card PCI Express x4 E1G44HTBLK

HP G2 Dual Port 10Gigabit Ethernet Card PCI-E 516937B21 $583.6 HP G2 Dual Port 10Gigabit Ethernet Card PCI-E 516937B21

Mellanox ConnectX-3 Gigabit Ethernet Card - PCI Express - 10/100/1000Base-T - Internal MCX312AXCBT $412.41 Mellanox ConnectX-3 Gigabit Ethernet Card - PCI Express - 10/100/1000Base-T - Internal MCX312AXCBT

Fujitsu Fast Ethernet Card - PCI - 1 Port - 10/100Base-TX - External FPCLN489 $33.11 Fujitsu Fast Ethernet Card - PCI - 1 Port - 10/100Base-TX - External FPCLN489

3Com Firewall PCI Card Ethernet 10/100Mbps RJ-45 3CRFW200B $92.75 3Com Firewall PCI Card Ethernet 10/100Mbps RJ-45 3CRFW200B

HP / Compaq Network Card Ethernet 10/100Mbps 2-Ports PCI 338478001 $25.6 HP / Compaq Network Card Ethernet 10/100Mbps 2-Ports PCI 338478001

HP Network Card Ethernet PCI 10/100BTX RJ45 D5013A $13.2 HP Network Card Ethernet PCI 10/100BTX RJ45 D5013A

QLogic Iscsi Ethernet PCI-X Card 1-Port QLA4010C $177.11 QLogic Iscsi Ethernet PCI-X Card 1-Port QLA4010C

HP Ethernet 10/100/1000Mbps 4-Ports RJ-45 PCI-E Network Card 436431001 $277.4 HP Ethernet 10/100/1000Mbps 4-Ports RJ-45 PCI-E Network Card 436431001

HP NC150T Quad Port GigaBit PCI Ethernet Card 367132-B21 $348.36 HP NC150T Quad Port GigaBit PCI Ethernet Card 367132-B21

HP Ethernet 10/100/1000Mbps 4-Ports RJ45 PCI-E Network Card 436431001 $234.36 HP Ethernet 10/100/1000Mbps 4-Ports RJ45 PCI-E Network Card 436431001

HP NC6170 Ethernet 1000Mbps PCI-X SX Controller Card 313560013 $373.75 HP NC6170 Ethernet 1000Mbps PCI-X SX Controller Card 313560013

Netgear RN12P2GE Gigabit Ethernet Card - PCI $250.99 10/100/1000Base-T 2 2 x RJ-45 Network Ready NAS 3200 Gigabit Ethernet Card Internal Netgear Netgear, Inc PCI RN12P2GE RN12P2GE Gigabit Ethernet Card RN12P2GE-100WWS www.netgear.com

HEWLETT PACKARD PLUGIN CARD PCI EXPRESS 10 GIGABIT ETHERNET $910.85 HEWLETT PACKARD PLUGIN CARD PCI EXPRESS 10 GIGABIT ETHERNETPLUGIN CARD PCI EXPRESS 10 GIGABIT ETHERNET Manufacturer : HEWLETT PACKARD UPC : 884962319055

StarTech.com 2-Ports PCI Express GigaBit Ethernet Network Card PCI Express 2 X RJ-45 10/100/1000Base-T Low-Profile $122.98 StarTech.com 2-Ports PCI Express GigaBit Ethernet Network Card PCI Express 2 X RJ-45 10/100/1000Base-T Low-Profile

StarTech.com Mini PCI Express Gigabit Ethernet Network Adapter NIC Card - PCI Express - 1 Port - 10/100/1000Base-T - Intern... $61.85 StarTech.com Mini PCI Express Gigabit Ethernet Network Adapter NIC Card - PCI Express - 1 Port - 10/100/1000Base-T - Intern...

Overland OV-ACC901005 Gigabit Ethernet Card - PCI Express $220.99 10/100/1000Base-T 2 2 x RJ-45 Network SnapServer SAN S2000 System Gigabit Ethernet Card Internal OV-ACC901005 OV-ACC901005 Dual Port Gigabit Ethernet Card Overland Overland Storage PCI Express RoHS Yes www.overlandstorage.com

Overland OV-ACC901015 Gigabit Ethernet Card - PCI Express $631.99 10/100/1000Base-T 4 4 x RJ-45 Network SnapServer SAN S2000 System Gigabit Ethernet Card Internal OV-ACC901015 OV-ACC901015 Quad-Port Gigabit Ethernet Card Overland Overland Storage PCI Express RoHS Yes www.overlandstorage.com

Startech ST1000SPEX4 PCIe Ethernet Card $350.63 4 Port PCI Express Gigabit Ethernet NIC Network Adapter Card

1 Port PCI 10/100 Mbps Ethernet Network Adapter Card - network adapter $6.99 StarTech.com 1 Port PCI 10/100 Mbps Ethernet Network Adapter Card - Network adapter - PCI - Ethernet Fast Ethernet - 10Base-T 100Base-TX

Intel I340 Gigabit Ethernet Card - PCI Express $330.99 10/100/1000Base-T 4 4 x RJ-45 Network Intel Servers Intel Workstations Broad selection from 10/100 Mbps to 10 Gbps, for copper or fiber, from PCI to PCI Express, BASE-T to SFP+, with network reach from 1 meter to 10 kilometers and in single- to quad-port configurations. Other form factors including custom mezzanine cards and express modules are available upon request. Category 5 E1G44HT Gigabit Ethernet Card I340 I340 Gigabit Ethernet Card Intel Intel Corporation Internal Low-profile PCI Express www.intel.com

This entry was posted on Monday, June 7th, 2010 at 9:03 am and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.