WhatsMyIPAddress.co.uk
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Why might I need to know my IP Address?
How is the IP routing table used?
How to translate an email address into an IP number?
Can one computer have many IP addresses?
Can every URL be translated to an IP address and vice versa?
Can I be identified through my IP address?
Can each computer in a network have a single IP when sharing a modem?
How can I look up a web site by IP address?
Why does my IP address change?
My IP address is wrong, Why is this?
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Every computer connected to the Internet is assigned a unique number known as an Internet Protocol (IP) address.
IP addresses consist of four numbers separated by periods (also called a "dotted-quad") and look something like 127.0.0.1.
Since these numbers are usually assigned to internet service providers within country-based blocks, an IP address can often be used to identify the country from which a computer is connecting to the Internet.
(Internet Protocol) The network layer protocol in the TCP/IP communications protocol suite (the "IP" in TCP/IP). IP contains a network address and allows messages to be routed to a different network or subnet. IP does not ensure delivery of a complete message, and the TCP transport layer is used to provide that guarantee (research TCP/IP for more details).
Because the numbers may be tedious to deal with, an IP address may also be assigned to a Host name, which is sometimes easier to remember. Hostnames may be looked up to find IP addresses, and visa-versa.
The logical name assigned to a computer. On the Web, most hosts are named WWW; for example, www.mycompany.com. If a site is composed of several hosts, they might be given different names such as support.mycompany.com and sales.mycompany.com. SUPPORT and SALES are the host names, MYCOMPANY the subdomain name, and COM is the top-level domain name. See HOSTS file, IP address and TLD.
Why might I need to know my IP Address?
For clients that require the facility we are able to restrict access to your website or web application so that only specific computers or networks on the Internet are able to access it. To do this, we need your IP address, which you can see above.
Note that if you are behind a NAT (Network Address Translation) Firewall or Router, then this may not be a true representation of your IP address. Instead it will be the address of the gateway connecting you to the Internet rather than that of your computer.
The only disadvantage of a dynamically-assigned IP address is that it can change each time you connect to the Internet. (This can also be viewed as an advantage, of course, as it makes it more difficult for hackers to track you down.) If you are using software that requires you to know your IP address, you may wish to visit myIPaddress.com whenever you reconnect to the Internet.
If you have a continuous connection to the Internet, your Internet Service Provider may assign you a "static IP address". A static IP address identifies your computer on the Internet using the same address as long as you remain with the same ISP. This is necessary if your computer is to provide services on the Internet, such as e-mail or web hosting.
An IP alias is an alias for a named group of IP addresses (including masks)
or hostnames. It is a mechanism where a single ethernet interface can respond
to multiple IP addresses. An IP alias may be in a completely different subnet
and domain than a host's primary IP address. This is often desired by WWW
presence providers. An IP aliasing is a step beyond a DNS alias, which is an
extra hostname for the same IP address. HTTP requests do not include the
host name, so a server has no way of knowing the host name to which a
particular request was sent. A server *can* determine the IP address to which
a particular request was sent and respond accordingly, so IP aliasing allows
one to have multiple independent servers on a single machine.
A global IP Address (Public IP Address) is the IP address which is assigned
uniquely with every internet connection in the world. Who is responsible
for global IP address assignment? There are four Regional Internet Registries
(RIRs) which are
responsible for doing global IP address assignment. Each maintaining a whois
database holding details of global IP address registrations in their regions.
They are ARIN (North America and sub-Saharan Africa), APNIC (Asia Pacific
region), LACNIC (Southern and Central America and Carribean), and RIPE NCC
(Europe and northern Africa). In contrast to global IP address which is unique in
the world, there are a big number of the same local IP adresses in the world
which belong to different local networks.
A local IP Address (Private IP Address) is an address that is used for
an internal network. A local IP address is perfectly unknown and not reachable
from internet (outside network). Local IP networks typically use a gateway
that is configured with Network Address Translation (NAT), which maps
local IP addresses to global IP addresses back and forth, to connect to
internet. Private IP addresses
are defined in the RFC 1918. They are:
Class Range Mask
A 010.xxx.xxx.xxx 255.000.000.000
B 172.016.xxx.xxx 255.255.000.000
C 192.168.xxx.xxx 255.255.255.000
A user agent is the client application used with a particular network protocol; the phrase is most commonly used in reference to those which access the World Wide Web. Web user agents range from web browsers to search engine crawlers ("spiders"), as well as screen readers and braille browsers used by people with disabilities.
When Internet users visit a web site, a text string is generally sent to identify the user agent to the server. This forms part of the HTTP request, prefixed with User-agent: or User-Agent: and typically includes information such as the application name, version, host operating system, and language. Bots, such as web crawlers, often also include a URL and/or e-mail address so that the webmaster can contact the operator of the bot.
The user-agent string is one of the criteria by which crawlers can be excluded from certain pages or parts of a website using the "Robots Exclusion Standard" (robots.txt). This allows webmasters who feel that certain parts of their website should not be included in the data gathered by a particular crawler, or that a particular crawler is using up too much bandwidth, to request that crawler not to visit those pages.
Three blocks of IP addresses are reserved for private use and are not routed over the Internet. Companies can assign these addresses to nodes on their private LANs at any time without conflict. See IP address, NAT and RSIP.
CIDR
From To Representation
10.0.0.0 10.255.255.255 10/8
172.16.0.0 172.31.255.255 172.16/12
192.168.0.0 192.168.255.255 192.168/16
NAT (Network Address Translation) is the technology to translate a local (private)
IP address used within internal network to a global (public) IP address known to
internet and vice versa. Typically, a company maps its local IP addresses to one
or more global IP addresses and unmaps the global IP addresses on incoming
packets back into local IP addresses. NAT is often built into routers. It receives
each packet from the local network and modifies the IP header to match the
global IP address of the router, before it is transmitted to the internet. The router
stores the local IP address, destination IP address and port number in a routing
table. When a request is returned on the same port, NAT matches the local IP
address that originated the request and modifies the IP header to match the
local address once again. If network traffic comes into the NAT router that is
not the result of a local network making an outbound request, the NAT router
does not know where to send that network traffic. So that traffic gets
ignored. This way, a NAT router will simply deny incoming traffic that it does
not understand, thus improve the local network security. NAT also conserves on
the number of global IP addresses that a company needs and it lets the company
use a single IP address in its communication with the world.
How is the IP routing table used?
The IP routing table stores information about destinations and how they can be
reached. There are a series of default entries based on the configuration of the
node. When an IP packet is forwarded, the IP routing table is used to determine
the next-hop IP address and its interface. For a direct delivery (the
destination is a neighboring node), the next-hop IP address is the destination
address in the packet. For an indirect delivery (the destination is not a
neighboring node), the next-hop address is the address of a router. The next-hop
interface identifies either a physical interface (for example, a network
adapter) or a logical interface (for example, a tunneling interface) that is
used to forward the packet. After the next-hop address and interface are
determined, the packet is passed to the Address Resolution Protocol (ARP). For
LAN technologies such as Ethernet and Token Ring, ARP attempts to resolve the
link-layer address (also known as the media access control [MAC] address)
for the next-hop address, and forward the packet by using the next-hop interface.
The following are the fields of a typical IP routing table entry: Destination (IP
address or a class-based, subnetted, or supernetted network ID), Network Mask
(bit mask used to match a destination IP address to the value in the Destination
field, also called Netmask), Next-Hop (IP address to which the packet is
forwarded, also called Gateway), Interface (used to forward the IP packet),
Metric (to indicate the number of hops en route to the destination).
How to translate an email address into an IP number?
You cannot translate email address into IP number, but you can translate for its domain name (the part after @ sign).
Can one computer have many IP addresses?
Basically yes, but usually one operating system has one IP address only. If your computer is running multiple OS simultaneously (e.g. with VMware or Virtual PC), then you can have multiple IP addresses on the same machine. But you can also configure your OS to have multiple IP addresses.
Can every URL be translated to an IP address and vice versa?
Every host name of URL can be translated to an IP address consisting only of numbers, but not vice versa. How is it done? more
Can I be identified through my IP address?
It depends on your internet connection. If you are connected directly to the internet, you will be identified through your IP address. Otherwise, if you are connected to the internet via proxy server, then your IP adrress will identify the proxy server.
Can each computer in a network have a single IP when sharing a modem?
If you use one modem to connect to the internet, it means you have only one global IP address. So each computer in the network can have different local IP address, but will share the same global IP addresss.
How can I look up a web site by IP address?
Just type "http://" + IP address on your browser address bar.
Why does my IP address change?
If you have a dial-up connection to the Internet or are using a computer that gets connected to the Internet intermittently, you're most likely picking up a dynamic IP address from a pool of possible IP addresses at your Internet service provider's network during each login.
My IP address is wrong, Why is this?
Similarly, if your computer is behind a "proxy server" or "web cache" (i.e., a computer that intercepts requests for web pages in order to speed up frequently-requested pages), the IP address displayed is probably the IP address of the proxy server or web cache -- not your computer.
Note that your computer may be behind a proxy server or web cache without your knowledge! A number of companies and Internet Service Providers use "transparent web caches", which intercept requests for web pages without any special configuration of your computer.
Refers to all the standards that keep the Internet running. The foundation protocol is TCP/IP, which provides the basic communications mechanism as well as ways to copy files (FTP) and send e-mail (SMTP). The Web added the HTTP protocol for downloading Web pages and HTML, XML and XHTML for formatting them. There are many others and many more are expected, as the Internet has become "the" arena for global standards. See TCP/IP, FTP, SMTP, HTTP and HTML.
Click Here for Further Detailed Information on Internet Protocol
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