For CCNA and CCNP candidates, it's hard not to laugh the first time you hear the phrase "router on a stick". Let's face it, that's a pretty silly term. But as those who have passed the CCNA and CCNP exams know, this is a vital exam topic that you must know how to configure and troubleshoot.
Basic Cisco theory states that for hosts in different VLANs to communicate, a Layer 3 device must be involved to handle the routing between the VLANs. That device is a router, and there are special considerations that must be taken into account for both the physical router itself and the configuration you'll be writing.
The router will be connected to a switch via a FastEthernet port (or higher). The router port cannot be a regular Ethernet port, since the router port will need the ability to send and receive data at the same time.
The configuration of the interface is where things get interesting. Let's say we have two VLANs that will be using router-on-a-stick to communicate.
Here is the VLAN information:
VLAN 20: 20.20.20.0 /24
VLAN 40: 40.40.40.0 /24
The port on the switch that will be connected to the router's FastEthernet port must be in trunking mode, and you must know the trunking protocol in use. We'll go with the Cisco-proprietary ISL here.
The physical FE port on the router will not have an IP address. The use of router-on-a-stick mandates the use of logical subinterfaces. While we don't have to use the VLAN numbers for the subinterface numbers, I've found this helps you keep the interfaces straight. One subinterface must be given an IP address in VLAN 20, and the other will have an IP address in VLAN 40
After creating subinterfaces fast 0.20 and fast 0.40, the config looks like this:
interface fastethernet0
no ip address
interface FastEthernet 0.20
ip address 20.20.20.1 255.255.255.0
interface FastEthernet 0.40
ip address 40.40.40.1 255.255.255.0
Believe it or not, you're almost done! Now we need the encapsulation statement under each subinterface. The subinterface statement must reflect both the VLAN number and the encapsulation type being used. When we're finished, the config would look like this:
interface fastethernet0
no ip address
interface FastEthernet 0.20
ip address 20.20.20.1 255.255.255.0
encapsulation isl 20
interface FastEthernet 0.40
ip address 40.40.40.1 255.255.255.0
encapsulation isl 40
And that's it! Your hosts in VLAN 20 should now be able to communicate with hosts in VLAN 40, and vice versa.
A couple of final troubleshooting points - the most common error with router-on-a-stick is to put the wrong vlan number in the encapsulation statement. Also, make sure you have configured the router's IP address in VLAN 20 as the default gateway for hosts in VLAN 20, and do the same for VLAN 40.
I hope you've enjoyed this look at router-on-a-stick. While the name may get a chuckle out of you, it's still used in quite a few networks out there, and knowing how to configure and troubleshoot it will get you that much closer to earning your CCNA and CCNP.
There are 4 color personality types. Red, Blue, Green and Yellow.
In a nutshell knowing what the different color personalities people have means you'll understand people better then they understand themselves.
At this point this tells you nothing. No worries it didn't mean anything to me when I first heard about personality colors. But man I wish I knew about this years ago, it would have saved me a ton of aggravation.
Everybody has a color type. And with that color type we act in a certain way. Certain things are important to us. We like to be talked to in a certain way. We like and dislike certain things.
Take me for example. Lets say you were calling me as a potential prospect.
What if you knew how I liked to be talked to? Knew what was important to me. Knew what I didn't like. Knew what I liked. Knew if I was over sensitive. Knew if I needed support. Knew if I like to have fun.
Knew if I would be teachable. Knew if I was money motivated. Knew if I would be a leader. Knew if I was creative. Knew if I needed all the facts and figures.... I could go on and on.
What if you knew all this information and soooooooo much more about me after only talking to me (anyone) for only a few minutes and then gained more and more insight to me the longer you talked to me?
Do you think this would impact your business and your personal life in a positive way?
If I have to answer that for you...honestly click away and go play a video game you're just wasting your time. (Sorry about that I had some guy tell me he saw no value in this. Gee no wonder he's not achieving all the success he could be.)
But for everyone else who sees the power of this. Would you not agree you'd have an unfair advantage on everyone else?
I can give you a brief overview of the four different personality colors. There is much more to learn but this will give you a good idea of the power of knowing color personalities. (They're in no particular order)
First there is Yellow. Yellow's make up 35% of the population and are open and indirect with their feelings. They are the best at using both sides of their brains. They are relationship and family orientated, logical, analytical and teamwork is very important to them. Their voice is soft and gentle and speak in relaxed tones.
Yellows have jobs like teachers, social workers usually any nurturing job. They like giving back to others. They don't like pushy people, aggressiveness, sudden change or animal cruelty.
Some of their weaknesses are. They are over sensitive, take things personally and will buy other peoples excuses.
Talk to a yellow slowly and relaxed and let them know they are appreciated.
Next is Blue (that's me). Blues make up 15% of the population. Blues are open and direct with their feelings. Very right brained, talk fast, very creative, must have fun doing things. Strong on family and relationships, spontaneous and enthusiastic.
Blues have jobs like sales (of any kind), singer songwriter anything that is creative.
They don't like not having fun they don't like facts and figures or being sold.
Their weaknesses are being unorganized, scattered and poor savers.
When you talk to a blue focus on fun, talk about excitement. Never try to sell a blue.
Next is Greens. Greens make up 35% of the population. They are indirect and self-contained with their feelings. Right brained, very logical, and analytical. Precise and need to have all the facts and figures. They are savers. Organized, task orientated and accurate. Let's get the kids to college. And they're the best negotiators.
Some of their jobs include, engineers, accountants, CPA, professor. Anything to do with logic and reasoning.
They don't like pushy people. Not having all the facts and figures. Not being on time, aggressiveness. Get depressed easily and are hard to please.
Some of their weaknesses are, they over analyze everything (to death). Hard to please and pessimistic about everything.
When speaking to a green, give them the facts and figures. You cannot overload a green with information.
And finally the Reds. Reds make up 15% of the population. Reds are direct and self-contained with their feelings. Reds are right brained. Their slogan is "It's my way or the highway" Forceful, stern and to the point. No chitchat, money is power, take action. Task orientated, Impatient, un-teachable, show me the money.
Their jobs consist of being CEO's, Attorneys, military leaders, and president of the bank.
Reds do not like losing control, indecision, small talk or crying. They don't like talking about time freedom, family or vacations.
Some of their weaknesses are having a big ego, domineering and un-teachable.
When you talk to a red you need to let them think you need them. They like being sold, close them, focus on money, and stroke their ego. Talk about your leaders income.
Now everything I just outlined about the different color personalities is not a judgment it's who people are.
Just imagine if you had this information the next time you talked to a prospect? How do you think your next call would go?
Learn this skill so the next time you're talking to someone and they say something in a certain tone or way or ask you a question. You'll know exactly why they're acting the way they are and why they are asking the questions they do.
Instead of taking things personally or getting frustrated, you'll say to yourself "Hey you're suppose to act like that or say that because you're a green" (pick a color)
Master this one skill and your business life and personal life will skyrocket. Guaranteed!!!
Until Next Time.
To your success,
Duffy Rogan
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
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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 alpha-numeric 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), such as www.defendingthenet.com , 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
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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
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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 devices 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
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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 are 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.