The Island of Logic

I don’t usually listen to NPR :), but a friend of mine sent me a link to a segment of the Diane Rehm Show that he heard on NPR. I listened to the segment and it is very good. Diane interviews Paul Kurtz, Alan Paller, Stephen Spoonamore, and Congressman Jim Langevin. They discuss the Cyber Security Threats that exist from sources like China, etc.. This is a 50,000 ft. view that can be understood by anyone, and does not contain all the technical jargon usually part of Geek Shows. This is enlightening to anyone that wants to understand more; what threats exist to their personal Internet security.

Link to Segment on the Diane Rehm Show

I have decided to publish this article again. I had posted this on the Internet about 4 years ago so that the students in my networking classes would have something to reference back to after I addressed the subject in class. I am going to post the article here again along with a video explaining IPv4 addressing (coming soon). I will post another article soon delving into the details of IPv6. This article here covers the decimal and binary math related to IP addressing and Subnet Masks. A well rounded knowledge of these concepts is critical for network engineers to know in order to design networks and implement security.

Ok, lets start out with a definitions of the terms. If you already know these, then good for you. These are my own definitions and formulas, not copied from anywhere. Please do not use these without giving credit, or gaining written consent.

TCP/IP: Transmission Control Protocol/Internet Protocol
Decimal: A numbering system with values from 0 to 9. Ten possible values. Also known as Base-10.
Binary: A numbering system from with values from 0 to 1. Two possible values. Also known as Base-2.
Bit: A single value in the binary system. Either a 1 or a 0.
Boolean Logic: A combinatorial system that uses the operators AND, OR, NOT, and XOR. Boolean logic can have one of two values true or false.
IP Address: The decimal representation of the binary value of the number that identifies a node on a network. A 32 bit number. I.E. 192.168.4.12
Broadcast: A network transmission that is sent to and processed by all the nodes on a subnet.
Multicast: A network transmission sent to and processed by group of nodes in a subnet.
Unicast: A network transmission sent to and processed by a specific node in a subnet.
Node: Anything that can have a IP address assigned to it.
Subnet: A mathematically segmented number of IP addresses that are on the same logical network (It does not have to be the same physical network, though it often is. Because of this it is sometimes confused with the ethernet contention domain.)
Broadcast Domain: All the IP addresses that receive the same broadcasts. Also a subnet.
Network ID: The decimal value of the ANDed IP address. Also the base value of the subnet. Always has the value of all 0s in the Host ID portion of the IP address.
Host ID: The portion of the IP address as defined by the subnet mask that identifies the node in the subnet.
Broadcast ID: The last IP address in a subnet. Cannot be assigned to a node. Is used for broadcast transmissions. Always the value of all 1s in the Host ID portion of the IP address.
Subnet Mask: A decimal representation of the amount of bits used to define the Network ID. I.E. 255.255.255.128
CIDR: Classless Inter Domain Routing. A shorthand method of defining a subnet mask. States the number of bits used to define the Network ID. I.E. 192.168.4.12/26 (the /26 is the CIDR notation)
Octet: A IP address is divided into four sections separated by decimal points. A section is called a octet. This is because it has eight binary bits.
Gateway IP address: The IP address that identifies the node that receives transmissions that are being sent to nodes that are not in the sending node’s subnet.
Integer: Whole numbers. Numbers without fraction or decimal. For example the integer of 2.67 would be 2.
Modulus: The simplest way to describe this is to say the remainder of a number divisable by another. In other words 8 mod 3 = 2. The remainder of 8 divided by 3 is 2.

Formula Variables:
A = Amount of Nodes
H = Host ID Bits
0 = Octet Value
N = Network ID
B = Broadcast ID
C = CIDR
U = Octet value counting from the left that is the value of “O”.

The math behind figuring out IP subnets is simple and can be done in your head as soon as you understand the concepts. It is just a conversion from binary to decimal. Below I have a chart with the math behind figuring the amount of nodes supported by a Subnet Mask. This covers subnets smaller than 255.255.255.0, but the math works the same for the larger subnets. Now let’s get into the math behind the madness. Let’s start with the formula for calculating the Octet (O) from the left that is the one to be used in the following Amount of Nodes equation, the formula is INT( C / 8 ) + 1 = U. This tells the Octet value, counted from the left that will populate O. Now to calculate the Amount of Nodes. Take 2 to the power of the amount of Host ID Bits multiplied by 256 to the power of 4 – U and then subtract a final 2 values for the Broadcast and Network ID since they are not addressable IPs, and the result will give you the amount of Nodes, so our formula is (2^^H) * 256^^(4-U) – 2 = A. Host ID bits is calculated by subtracting the CIDR from 32 (The amount of bits in a IP address) and a modulus of 8 (The amount of bits in a single Octet). So our formula for Host ID bits is (32 – C) mod 8 = H. So lets take the IP address and subnet of 192.168.12.129/26 and lets calculate the amount of nodes. We need to first get the Host ID bits so as in the previous equation we subtract the CIDR from 32 with a modulus of 8. That would be 32 – 26 which is 6, then 6 divided by 8 with the remainder of that division being 6, so our answer is 6 Host ID bits. Next we use the amount of Nodes formula (2^^H) * 256^^(4-U) – 2 = A. This would be (2^6) * 256^^(4-4) – 2 = 62, or in words, 2 to the power of 6 multiplied by 256 to the power of 4 minus 4 and then a final 2 values are subtracted for N and B since they are not addressable and the result is 62, so 62 is the amount of Nodes we can have in that subnet.

Subnet Masks and their corresponding Node ranges:

Ok, now that we see that calculating the amount of Nodes is easy lets look at the formulas for calculating the Network IDs and Broadcast IDs. Lets use the same IP address of 192.168.12.129/26. The CIDR is 26 so remember our previous formula for calculating the Host ID bits (32 – C) mod 8 = H. So lets do it again, 32 – 26 mod 8 = 6 Host ID bits. Now for the formula for calculating the Octet (O) from the left that is the one to be used in the following Network ID equation, INT( C / 8 ) + 1 = U, so in this case since the CIDR or C value is 26 the formula would read like this INT( 26 / 8 ) + 1 = 4, or in words, the integer of 26 divided by 8 which is 3 plus 1 equals 4. That means that the Octet value to populate O will be 129, the 4th Octet from the left. Ok, now lets use the formula for calculating the Network ID (Int(O / 2^^H)) * 2^^H = N. Lets work through it, the integer of 129 divided by 2 to the power of 6 equals 2, or the integer of 129 divided by 64 equals 2. Then the rest of the formula is 2 multiplied by 2 to the power of 6,  or 2 multiplied by 64 which equals 128, so our Network ID is 128. (Int(129 / 2^⁶))*2^⁶ = 128. Ok, now lets calculate the Broadcast ID. Now the entire formula for that would be (Int(O / 2^H))*2^H + (2^H – 1) = B, but since we already know the Network ID we can simple do N + (2^H – 1) = B. Lets work through it, 128 + (2^6 – 1) = 191, or in words, 128 plus 2 to the power of 6 which would be 128 plus 64 minus 1 and that equals 191. Ok then, our broadcast is 191. Lets see all the results of 192.168.12.129/26.

Network ID: 192.168.12.128
Broadcast ID: 192.168.12.191
Amount of Nodes: 62

Formulas:
H = (32 – C) mod 8 (Excel formula “H = mod( 32-C,8 )”)
A = (2^^H) * 256^^(4-U) – 2
U = INT( C / 8 ) + 1
N = (Int(O / 2^^H))*2^^H
B = (Int(O / 2^^H))*2^^H + (2^^H – 1) or N + (2^^H - 1)

These formulas work fine in Excel so you can simply copy and paste them in if you like. Obviously you will have to replace the variables with cell numbers, but that is a given.

So now you are going to say, how do I calculate the CIDR if all I am given is the subnet mask? I thought you might ask. I considered demonstrating this with a rather complicated equation, but I think a chart will simply be easier to use and remember. Remember that a subnet mask is simply the decimal representation of the amount of bits used by the Network ID. The boolean AND logic is used by the TCP/IP stack to AND the IP address against the subnet mask and the result is the Network ID. The subnet mask of 255.255.255.192 converted to binary would be 11111111.11111111.11111111.11000000. The CIDR is simply a count of the amount of bits from the left that are used to define the Network ID. If you notice the first, second, and third octets are all 1s since the binary value of 255 is 11111111, so all 8 of the bits are used for the Network ID in each of these octets. The last octet is 192 and the binary value of that is 11000000, so there are 2 bits used in this octet for the Network ID. So you can simply count the amount of 1s to get the CIDR or do 8 + 8 + 8 + 2 = 26 and that is the CIDR. To get the CIDR just use the chart below and add the bits for Network ID together to get the CIDR. I.E. The CIDR for 255.255.240.0 would be 8 + 8 + 4 = 20.

Subnet Mask Decimal and Binary Equivalents:

It has been my opinion for sometime now that if a network engineer is incapable of performing these simple functions in his head, then he should look for a job elsewhere. The reasoning behind that is if they are not able to perform this simple task what other essential networking tasks are they not capable of. General networking theory knowledge is so lacking today; sometimes I wonder how some people are capable of performing their jobs (Google is good). I have some fellow engineers that disagree with me on this opinion, you can guess who they are. :)

I have decided to write this since I am getting tired of the incorrect definition that is being given by the media and academia to right wing Conservative politics. The common misconception that I keep hearing and reading is that Fascists and Nazis are extreme right wing Conservatives. I have seen this on the History Channel, read it in news stories, and seen it in text books. What pin-headed, whacko liberal was able to get this as an accepted definition of extreme right wing politics, and who are the majestic mountains of colossal ignorance that keep repeating it. Below I have created a political scale.

(Take special note that Republicans are not very close to the Conservative portion of the graph, this has sadly become the state in the last ten years.)

I contend that extreme right wing politics or extreme Conservative politics is Anarchy instead of Fascism or Naziism. The reason it is Anarchy is because the base definition of Conservatism is limited or less government and Anarchy is the absence of any form of authority or government. Anarchy would then be extreme Conservatism. Extreme Liberalism on the other hand is Communism or Socialism. The primary tenant of Liberalism is that more government is the answer to our problems. (Poverty: the New Deal. Retirement: Social Security. Education: Government run public schools. Health Care: Hillary Care. Gas Prices: more restrictions on oil companies, or in the words of the lovely and gracious Maxene Water’s “… this liberal will be all about socializing..basically..TAKING OVER and the government running all of your companies…” (watch below). etc. etc….)

Now what poor Maxene was trying to say here was Nationalize instead Socialize, but in her faux pas she actually stated the truth. Nationalizing the oil industry would be Socialism. This would be akin to what our good old buddy Hugo Chávez of Venezuela did. This is funny and we laugh at her stupidity now, but when too many stupid people like her get into power suddenly their stupidity is no longer funny.

Communism and Socialism are about extreme government control; the government being in control of every aspect of people’s lives, restricting freedoms and transferring wealth, trying to put everyone on a equal playing field. Conservatism on the other hand believes in getting out of peoples lives. It believes that when people are given freedom and the ability to be all they can be without the government coming down on them, they will excel. Nazism and Fascism are left wing forms of government, because they are types of extreme government control. I find it very interesting that Benito Mussolini, one of the primary names associated with Fascism was a Socialist before becoming a Fascist. I doubt his political views changed that much, but yet the form of government that he championed is considered to be “extreme right wing”!? You may say that this is a simplistic way of viewing the political spectrum, and that it is much more complicated than this. Well I agree with Einstein “Most of the fundamental ideas of science are essentially simple, and may, as a rule, be expressed in a language comprehensible to everyone.” I believe that the basic tenants of the political views are simple and one of the primary measuring sticks that can be used is the level of government control. There are however aspects of political views that transcend this measuring stick. For example, a strong military is the policy of most Communist governments and also a value of the American Conservative movement. A strong military however is more or less apposed by the American Left. Fascist and Nazis supported Militarism which is an extreme view of a strong military. So there are views that are accepted all across the government control spectrum that do not necessarily apply to the level of government control. The right to life or antiabortionism would also fall out of the category of government control and is more of a social or religious view. There are some views like the right to life which are part of a particular country’s form of Conservatism, like American Conservatism. Another country’s Conservative movement may not have the tenant of the right to life or a strong military. Don’t be confused, these are simply aspects of the American form of Conservatism, and not part of the simple definition of political Conservatism. The reason the political spectrum should be measured by the level of government control is because more political policies can be measure with this stick then with any other. The American Constitution is a politically Conservative document because its primary role is to restrict the powers of the Federal government. The founding fathers were so interested in restricting the control of the government that their first form of the Federal government was under the Articles of Confederation which made the Federal government so weak that the thirteen colonies almost fell into Anarchy. The founding fathers in the Bill of Rights made a list of rights that shall not be infringed upon by the Federal government. This is a politically Conservative view that is being continually attacked by the American Left. Liberals believe that certain types of speech should be restricted, hence the age of Political Correctness. That citizens do not have the right to bear arms, even when the Second Amendment in the afore mentioned Bill of Rights explicitly gives that right to its citizens. American Liberals are then left wing and believe in more government restrictions and control and the American Conservatives are right wing and believe in less government control hence these political views land where they are on the political spectrum graph. This view point will probably never be taught in any Political Science class, but that is because this explanation is far to simple for that meathead of a professor to wrap his pee sized brain around. Besides you don’t need a PHD to understand it.

My parents showed me this video. I think I am going to see if I can get the Quartet to sing it. This is sadly funny. I know that is an oxymoron, but it is true. No, I am not homophobic (ok, maybe just a little). I don’t hate homosexuals, but just as the video says it is not natural and not what God intended. Sorry, if you put all the gays on an island by themselves, that crowd would be gone in one generation. The Darwin Theory applies here, Survival of the Fittest.

This is so funny. This was emailed to me by a co-worker. Admittedly the language is a little rough, don’t watch if you are easily offended. This is so typical if you are a IT guy though. This guy does some classic moves like deleting your boss’s sent email so that you can claim he never sent an email to you. Setting a user’s desktop background to a picture of their desktop and then deleting all their icons. He used the same method that I used when I was a network admin to users when they would call. I would ask them if they had rebooted their machine even if it was something as simple as a missing icon or something. Another classic move is to use VNC or something similar to get into a user’s desktop while you are on the phone with them, and asking them to login. You can kindly add some additional characters while they are typing their password. You then berate them for their typing skills or their stupidity for forgetting their password. This will always bring laughs to anyone in the IT Dept. Granted it probably does not improve relations between IT and users, but it sure is funny.

This Video was create by Website is Down: http://dpt.thewebsiteisdown.com/dpt/

http://www.cnn.com/2008/POLITICS/07/10/rove.subpoena/

It’s about time that someone in the Bush Administration showed some onions. What in the world is Congress doing anyway? If they would pay as much attention to gas prices and drilling for our own oil; we wouldn’t be in the economic state we are in right now. This is such a non-issue that it is insane. Bill Clinton fired all 93 of the U.S. attorneys in March of ’93 and there was no Congressional investigation at that time. The U.S. attorneys serve at the whim and pleasure of the President of the United States, if the President wakes up in the morning with a little indigestion from a undercooked potato and he wants to fire all the Federal attorneys he has the Constitutional right to do so. “Congress, get a life and deal with some issues that matter”.

Read more about this at the Wall Street Journal.

http://www.opinionjournal.com/editorial/feature.html?id=110009784

I think it is great that Microsoft provides a limited edition of their kernel free for a Pre-boot environment. It is a great troubleshooting tool. Microsoft has provided the PE disk since Windows XP, but it was at one time only available to OEM’s. This disk will work with all versions of Windows and even other OS’s, as long as it has a file system that is readable by Vista. I just got done using a PE disk on a unbootable machine (wouldn’t even finish loading in Safe Mode) at a customer to restore the registry from a System Restore point. Works like a charm.

Below are the instructions on how to create a Windows Vista PE disk.

• Download and install the Automated Installation Kit from Microsoft. (http://www.microsoft.com/downloads/details.aspx?FamilyID=C7D4BC6D-15F3-4284-9123-679830D629F2&displaylang=en) 
• Open the AIK Command Prompt. Start Menu>All Programs>Microsoft Windows AIK>Windows PE Tools Command Prompt.

• Next you will use the “copype” command to create the Win PE structure based on the processor architecture that you have, x86 or AMD64. In this case I am using the “copype x86 c:\windowspe-x86″ command.

• The resulting output of the “copype” command will generate a folder structure under C:\windowspe-x86. In this folder will be the necessary files to make a bootable ISO file or a WIM image file that can modified and deployed with ImageX. In this case we will just create a bootable ISO image file.

• The command that can be used to generate the ISO file is “OSCDIMG -bc:\windowspe-x86\etfsboot.com -n -o c:\windowspe-x86\iso C:\windowspe-x86\win_pe.iso”. The -b option specifies the path to the file containing the boot sector. The -n option allows file names longer then the DOS 8.3 format. The -o option is used to optimize the amount of space used by encoding duplicate files only once. The command will generate a bootable Windows Vista PE disk in the C:\windowspe-x86\win_pe.iso location. You can then burn this ISO to CD using any of your favorite CD burning software packages, like Nero, Roxio, etc.

Lawyer: Lawsuit possible after teen killed by Six Flags ride (http://www.wistv.com/Global/story.asp?S=8580338)

I know I am weighing in a little late on this story, but when I was watching Fox News yesterday morning and all the “experts” were arguing about whether Six Flags was liable or not, I decided that I had to say something. Besides everyone knows that I can’t shut-up about anything. My question is, “Whatever happened to personal responsibility?”. Everything is always someone else’s fault. Criminals aren’t responsible for their actions anymore, it was their rough childhood, it was the Twinkies they ate that clouded their judgement, they were insane at the time, etc., etc.. If someone does something stupid, it’s never their own fault. Humans are known to do stupid things from time to time, and sometimes they die because of it. Come on, the kid crawled over two six foot high fences, covered in warning signs. Obviously, he really didn’t have much of a head to lose. The last time I looked, city streets, subways, and railroad tracks aren’t surrounded by fences and warning signs, but it is common knowledge that if I run onto any of these and there is oncoming traffic or trains, that I will probably die. I haven’t heard of the city government getting sued the last time a kid ran into traffic after his ball. Instead of someone getting awarded a large settlement in this case the kid should instead be awarded a Darwin Award. The “pop” noise that was heard was Mother Nature sanitizing the gene pool. Ok, that was a little sadistic and cruel, and my sympathy and condolences do go to the family. I do sympathize with them however, primarily because my own family will probably also experience my untimely death because of some stupid action on my part. I am simply basing this on a past history of stupid accidents that I have had. I do beg of my family however, to not file a lawsuit on my behalf. It will be my fault for being stupid. I do not need the stupid action that resulted in my death aired on the 5 o’clock news and printed in the local newspaper headlines, Local Stupid Man Performs Stupid Action That Results In His Death, Family Suing. Please, just dig a hole and kick me into it, and tell everyone that it was just a misfortunate accident and spare them the details. I do want to leave with a small shred of dignity. You may say, “What a dumb subject for Independence Day.”, but I say that this fits right in with the ideals of the Founding Fathers when they penned the Declaration of Independence. They championed the ideas of freedom and personal responsibility. We just need to get our country back to those founding ideals. I would like to give this story my own headline: Lawsuit possible despite teen being killed by his own stupidity.

Now a case that does deserve a lawsuit is the story about the woman who died on the Emergency Room floor. This is disgusting. (http://www.cnn.com/2008/US/07/03/hospital.woman.death/)