The earliest records of beer were written around 7000 years ago by the Sumerians. It is said that the Sumerians discovered the fermentation process by accident. It is not known exactly how this happened, but it could be that a piece of bread or grain became wet, and a short time later, it began to ferment and made a pulp that caused people to become drunk. A seal around 4,000 years old is a Sumerian "Hymn to Ninkasi", the goddess of brewing. This "hymn" is also a recipe for making beer. A description of the making of beer on this ancient engraving in the Sumerian language is the earliest account of what is easily recognised as barley, followed by a pictograph of bread being baked, crumbled into water to form a mash, and then made into a drink, that is recorded as having made people feel "...wonderful and blissful". It could even be possible that bread was first baked to be a way to make beer that is easy to carry around. The Sumerians were probably the first people to brew beer. They had found a "divine drink" -- they felt it was a gift from the gods.
"Normal" beers have around 3-5 % alcohol (for the volume, i.e. in 100ml beer there is 3-5ml alcohol). In brewing beer, the amount of alcohol can be made more or less quite easily. The Belgian types of beer are made by adding more sugar. Through the fermentation, this will then turn to alcohol. Today, there are beers with between 2% and about 16% of alcohol (about the same alcohol content as wine). Spirits can have up to 80% alcohol. Some beer labels say there is no alcohol in them because it was taken out later. This is not completely true, though. Beers "without alcohol" usually do have less than 1% of alcohol.
IP address
An IP address (short for Internet Protocol address) is a label which is used to identify one or more devices on a computer network, such as the internet. It can be compared to a postal address. An IP address is a long
number written in binary. Since such numbers are difficult to communicate, IP addresses are usually written as a set of numbers in a given order. Devices using IP addresses use the internet protocol to communicate.
The Internet Assigned Numbers Authority assigns IP addresses to regional internet registries (RIRs). The RIRs assign them to Internet Service Providers. Internet Service Providers then assign IP addresses to their customers. Very often, people have a router or gateway at home, to which they connect computers, printers, and other devices. These routers or gateways are often configured to assign "local" IP addresses to the devices that are connected.
Each address has two parts: One that specifies the computer or group of computers, and another which specifies the network. A device can have more than one IP address. Certain types of IP addresses are used to address a group of devices, while others are used to address only one device. Certain types of addresses are unique, others can be re-used. A number of IP addresses are used for special purposes, for example to obtain an IP address automatically.
An IP address is converted to physical or Media Access Control Address using the Address Resolution Protocol (ARP). If an IP address is your phone number, then your MAC address is your name. You may change your phone number, but your name will not change.
Suppose one of our friends wants to meet us but they don’t know our address. He asks for our address and then we give our address (Example: 123 Main Street, Anytown, USA). After giving the address, he or she can easily locate our address. The same thing is done in case of internet. Every network is assigned an address.
IANA (Internet Assigned Numbers Authority) allocates the IP address. IANA is responsible for the IP addressing system.
An IP address is a long binary number, made of ones and zeros. An IPv4 address is 32 binary digits (or bits) long. An IPv6 is 128 bits long, allowing many more IP addresses to be used. IP addresses are usually written in human-readable form, where 8 bits are grouped into one octet. IPv4 addresses are usually written as a group of four numbers. Each number can take a value from 0 to 255. IPv6 addresses are written as a group of eight hexadecimal numbers. Many Ipv6 addresses contain many zeroes. There are special rules which say that in certain cases, these zeroes do not need to be written.
Certain IP addresses can be assigned freely on the local area network. Since they are not unique, they are not routed on the internet. The addresses which can be freely assigned are called private IP addresses, and the ones which are unique are called public. To be routed, a private address needs to be translated into a public one. This process of translating between private and public addresses is called network address translation, or NAT. Routers and firewalls often also perform this task.
There are three different types of addresses:
There are different ways of getting a new IP address. One of them is called Bootstrap Protocol (usually shortened to BOOTP). The device that needs a new address, does not know what network it is in, so it uses an IP address of all zeroes (0.0.0.0) which it sends as a broadcast to the current network, on a special port. In addition, it sends the MAC address of the network card, plus a 4 byte random number. The BOOTP server will send a reply, also as broadcast, addressed to a different port. The reply will contain the mac address of the client, the random number, and the IP address of the client. When the client receives the data, it will set the address specified. If the BOOTP server is configured that way, it will also send the IP address and hostname of the BOOTP Server, the name and path to a file which should be loaded to boot the client (using TFTP) or the name of a directory, which the client should mount using NFS.
DHCP extends BOOTP, and allows to send more information, such as the address of a time server, or information which is useful for routing.
IP addresses obtained automatically can be dynamic or static. Static addressing means the same machine will always get the same IP address. With dynamic addresses, a device will get the next address which is not used. Dynamic addresses which are used need to be reviewed from time to time. If they are not renewed, they can be used for other devices.
With IPv4, each address consists of four 8-digit binary numbers, called octets. An IPv4 address is 32 bits in total. The biggest number one can make with 8 regular digits is 99,999,999, but the biggest number one can make with 8 binary digits is 255 (11111111 in binary), so each octet can be any number from 0 to 255.
An IPv4 address could look something like this:
Each octet is converted to its decimal form and separated by a period.
There are are also special meanings associated with two different ending numbers. In general, a last number of 0 stands for the network (called "base address"), and a last number of 255 stands for all hosts on that network (called "broadcast address"). Computers that are on the same local network share 3 of the 4 numbers. A computer can be on more than one network. It can also have several names.
The problem with IPv4 is that it only allows for 4.3 billion addresses, and we've almost used them all. To delay this, Network Address Translation (NAT) was created. Network Address Translation has a network share one "public" IP address and give every computer on the network a "private" IP address. Everyone living in the same house uses the same address, but mail can be meant for multiple different people living in the house.
There are some IP addresses that are reserved for special purposes. For example, the address "127.0.0.1" is called the Loopback Address and will "loop back" any packets sent to this address back to the computer that sent them, like sending mail to yourself. Although this may not seem useful, it is used to test servers.
It identifies the class of a network.
It identifies the host on a network.