IP Mango

2008-10-13T15:58:00.007+05:30

IP Tutorials

This Blog contains several tutorials on topics related to IPs . Check out the "Tutorials" label to find and read the tutorials.

Voice Over Internet Protocol (VoIP) - IP Telephony - Explained

2008-10-12T15:02:00.006+05:30

VoIP - Voice Over Internet Protocol - A REVOLUTIONARY TECHNOLOGY

VoIP (Voice Over Internet Protocol) also referred to as IP Telephony, Internet Telephony and Broadband Telephony. It is a protocol which is used for the transmission of analog audio signals through the Internet or any other network where data is transmitted in the form of packets . Analog audio signals are same as the signals/voice which we hear on the telephone. VoIP converts analog audio signals into digital data packets. Then the digital data is compressed and broken down into small packets and carried over a network. Once they reach their destination, they are reassembled and converted from digital data back into analog signals so that the receiving node can hear the voice.

Using VoIP you can make free calls or decreased cost calls on the Internet using additional hardwares (eg :- mic.). There are several VoIP providers on the net and they have several calling plans. Paying a small amount to the VoIP providers you can make calls and get services like better sound quality, reduction of you phone bill, etc. For fast VoIP service a broadband connection is quite necessary.

There are two types of PSTN-to-VoIP services -

Direct inward dialing (DID) - DID will connect a caller directly to the VoIP user.
Access numbers - They require the caller to provide an extension number for the called VoIP user.

Several ways to place a call through VoIP :-

ATA (Analog Telephone Adaptor) - Most common and an easy way to place a call. The ATA connects a standard phone to your computer/your Internet connection for use with VoIP. The ATA takes the analog signals from your phone and converts it into digital data for transmission over the Internet.
IP Phones -- These specialized phones look just like normal phones with a handset and buttons. IP phones connect directly to your router and have all the hardware and software necessary right onboard to handle the IP call.
Computer-to-Computer - The easiest way to place calls. You just need additional hardwares like microphones, speakers, sound card, earphone and a fast Internet Connection like broadband. You need not pay any fee except to your Internet Service Provider.

Certain Advantages/Benefits of VoIP -----

Low monthly fee leading to the reduction of monthly phone bills.
No Taxes.
Long Distance and International Calls are cheap.
Uses packet switching and time consumption is during data transfer.
Data compression during the transfer of digital data.

Certain Disadvantages of VoIP -----

Some VoIP service providers do not have Emergency 911 operator.
VoIP will go down if home power goes down/cuts or the broadband internet connection goes down/is lost.
VoIP can be easily influenced/harmed by viruses or exploits or some other kind of hacking. Developers are working to counter-attack this problem.

Display IP Addresses of all the nodes/hosts on LAN/on a network

2008-10-12T12:21:00.001+05:30

Obtaining a list of IP addresses/MAC addresses of all connected nodes/hosts on a network in Linux/Windows/MAC/any OS :-

ONE METHOD
Download Angry IP Scanner --- another IP scanner tool
Download Link :- http://www.angryziber.com/w/Download
Enter the range of your network IP addresses.The scanner will then show the status of each node, i.e.,
whether a host is "alive" or "dead" and it will also show the IP Address of each node.

ANOTHER METHOD
Download NMAP ----- a security scanner / a port scan utility
Download Link :- www.nmap.org/download.html
To get the list of IP addresses with nmap, use this command:
nmap -sP "range of your network IP addresses"
For example :- nmap -sP 192.168.1.0/10

Cyclic Redundancy Check (Error)

2008-10-12T11:11:00.000+05:30

A cyclic redundancy check (CRC) is error detection method to check whether the transmitted data or file is corrupted or not. It is a type of hash function used to produce a checksum – a small, fixed number of bits. The checksum is used to detect errors after transmission or storage. A CRC is computed and appended before transmission or storage, and verified afterwards by the recipient to confirm that changes occurred on transit. CRCs are simple to implement in binary hardware, are easy to analyze mathematically, and are particularly good at detecting common errors caused by noise in transmission channels.If you get this error, it means that the file being read by your PC or software is corrupted.When data is transfered, it is usually in small blocks and each block is given a CRC value.If the file gets corrupted while transmission due to noise or any other problem, the CRC value which is sent alongwith data packets wil not match with CRC value calculated at recievers end. Then the cyclic redundancy check error will appear.

Cyclic redundancy check(CRC) code provides a simple, yet powerful, method for the detection of burst errors during digital data transmission and storage. CRC implementation can use either hardware or software methods.

Less frequent causes of CRCs are the result of system crashes, and buggy software, incomplete downloads (often identified by the misleading message 'This is not a valid Windows file', 'This is not a valid win32 application' or 'Corrupt Zip file'). If this problem happens frequently with downloads, try using a download manager.

CRC Error while reading CD/DVD :-
The most common times you will see the cyclic redundancy check error message is when trying to read data from a damaged CD or DVD. Just before it appears,
your CD/DVD drive will probably grind and whirl away - your PC may also become a little sluggish.Normally, when CD/DVD drives get a CRC message from a disc,
they try to read the disc again - hence the grinding sound. After several failed attempts, they give up and display the redundancy check error. The problem can be
hardware (loose cables, failing drive), software or damaged media. In most cases checking and cleaning the disc is the easiest way to overcome the problem. If different clean discs produce the same error, it is likely to be a hardware issue (check the discs in another drive). Another common cause of these errors is poorly burnt CDs and DVDs - especially those that had numerous or severe buffer underuns. USB burners suffer from this problem when the burn speed is too high (generally above 4X-8X).

There are several ways that a checksum/CRC error could happen :-
A Bad Write: if the device that wrote the media had a problem while writing, it could have written the wrong data.

Dirt in the Writer: dust or other obstructions in a CD or DVD writer can interfere with laster and cause the bad data to be written.

Bad Media: poor quality media, particularly CDs and DVDs, can sometimes "not take" the data that's written to them. Perhaps there's a flaw in the physical media. These types of flaws may not be visible to the naked eye - even a one-bit error can cause a CRC calculation to fail.

Bad Write Alignment: It's fairly obvious that on CDs and DVDs data is written in a circle on the media. However exactly where that circle lands is dependant on the alignment of the drive. It could be slightly off-center, or skewed in some way. This is frequently the case if a CD or DVD reads perfectly on the drive that wrote it, but fails when read on other drives.

Scratches and Other Damage:CRC checking is most commonly thought of as a way to detect errors that result from physical damage to the media after it's been written. a tiny scratch, if in the wrong place, can do damage.

Dirt in the Reader: much like dirt in the writer, dust and other particles can interfere with a CD or DVD reader's ability to read the media properly.

Bad Read Alignment: again, much like bad write alignment, if the reader isn't tracking to the same "circle", it may not be able to read the data. Some drives are better at compensating for this than others.

Bad Reading Drive: finally, it's always possible that the CD or DVD drive itself is having a problem reading in general.

If you have a CD or DVD that is reporting a CRC error try reading it on different drives

If the discs are damaged, you'll probably need a recovery tool to get back your data.

CRC Error in Network / Modem transmission :-
If you are attempting to open the file from a network / modem it is likely the network either is encountering collisions or other errors during the data transmission.

Note:- If the file is being sent through a session such as FTP or Telnet it is possible that it may not be sent properly.If the file is a text file, the file must be sent as either ASCII or TEXT mode.If, however, the file is a program or non-text file, it must be sent as a Binary file.

Attempt to re-send the file.
Try Alternate method of sending the file.
Verify the file was sent properly (ASCII / TEXT / Binary).
Verify with Network Administrator that the network is not experiencing issues.
Removable media issues.

Computation of CRC is based upon the mathematics of arithmetic modulo two.It is based on polynomial arithmetic.

Specify or Change your Lan IP Address in Windows

2008-09-18T15:57:00.006+05:30

Step 1 : Go to Control Panel and then to Network Connections.

Step 2 : Right-click on Local Area Connection and click Properties.

Step 3 : Under the General tab click Internet Protocol (TCP/IP) and click Properties.

Step 4 : In the 'Internet Protocol (TCP/IP) Properties' window, select "Use the following IP address" if it is not already selected and specify or change the new IP address you wish to use. While entering this data you can also specify or change the subnet mask and default gateway.

IP Packet Structure explained

2008-09-18T12:39:00.002+05:30

A packet is a unit of data carried over a computer network.When data is transmitted from one device to another it gets breaked up into small chunks called packets which reassemble on reaching their destination device.A packet structure consists of three parts which are as follows:-

1.Header - It consists of the information or instructions which the packets needs to obey.The header consists of :-

Version(Occupies 4 bits) - Version of the packet(ipv4 or ipv6).

IHL(Internet Header Length)(Occupies 4 bits) - Header size of the packet in 32 bits.

Type of Service(Occupies 8 bits) - The service priority desired.

Total Length(Occupies 16 bits) - Length of the packet.

Identification(Occupies 16 bits) - A value set by the source(sender) helping in the reassembling of the fragments of the packet.

Flags(Occupies 3 bits) - Controls various flags.For eg:-there is a flag which decides whether a packet should be fragmented or not.

Fragment Offset(Occupies 13 bits) - Identifies the postion of the fragment in the packet.

Time to Live(Occupies 8 bits) - Denotes the span of time till which the packet will continue to exist over the network.

The Protocol(Occupies 8 bits) - TCP,UDP,etc..The packets have to follow these set of rules.Protocol defines the type of packets carried over a network,i.e.,whether they are chat packets,email packets,etc.

Header Checksum(Occupies 16 bits) - Error checking may be done if certain fields like the 'time to live' may alter.

The Source Ip address(Occupies 32 bits).

The Destination Ip address(Occupies 32 bits).

Options(variable size) - They have to be implemented by all kinds of nodes.

2.Payload - The body of the packet which comprises the actual data which is sent by the sender to the destination.

3.Footer - It tells the receiver/destination device that the packet has reached its end.An error checking may occur.

Proxy Servers Explained

2008-09-18T12:38:00.004+05:30

A server(a program which provides services/a computer running that program) which comes between an user and any network or website ensuring the user security.It intercepts all kinds of requests sent by the user to the real server which he wants to access(for eg:- the server of google).It just acts like a default gateway changing the identity of the user when he accesses some kind of Internet resource.When the user requests some service(songs,videos,etc.) from a server,the proxy intercepts the user's request and then acts as a proxy(on behalf of the user) for the user throwing upon the request to the real server.The proxy may not also request to the real remote server if the service which the user has asked for is present in the proxy server's cache.
Main functions of a proxy server are as follows :-

1.Ensuring Security - A user can become anonymous on the Internet while surfing or chatting using a proxy as the proxy requests to the real remote servers on the behalf of the user.It alters the IP address of the user by assigning him a random IP address.Thus,our Ip address is hidden and so nobody can retrieve any information about us.

2.Caching - A proxy server has a cache in which it stores the services by saving them when it retrieves them from the specific server from frequent requests.Therefore,whenever a user asks for a service and is that service is present in the cache of the proxy server then the proxy server need not contact to the real remote server and provide the service from its cache only leading to fast accessing and surfing.

3.Filter requests - Sometimes teachers in school block certain websites,resources or services on the net to prevent the students from accessing those.At those times proxy servers can be used to filter out requests leading to the accessing of those resources.

Just perform a search at google for a list of proxy servers.

Port Scanner Scanning

2008-09-17T21:14:00.001+05:30

Disclaimer : The information provided below is only for educational purpose . The author is not responsible for any misuse of the information and discourages any illegal use of it.

[Under Construction]

WHOIS and IP Address Location / Geolocation Explained

2008-09-17T20:23:00.000+05:30

WHOIS - A worldwide database maintained by the servers of non-profit organizations and corporations like ARIN,RIPE NCC,APNIC,LACNIC and AfriNIC(belonging to Regional Internet Registries) containing a listing of domains.The database of all these servers have been referenced amongst themselves.Hence,if a query is made to AfriNIC for a domain name whose record of information belongs to ARIN,still AfriNIC will show the information relating to that query.The WHOIS database is queried to retrieve information like IP address,registrar,status,company name,address,domain name server etc. about a domain name.Websites providing WHOIS service reply upon WHOIS servers belonging to Regional Internet Registries to retrieve information and present before the user.

Anybody can simply perform an ip WHOIS query or a domain WHOIS query at Ipmango.An example of WHOIS data returned for www.ipmango.com from the WHOIS query at Ipmango is:-

Whois data for Ipmango
Registration Service Provided By: INC
Domain Name: IPMANGO.COM
Registrant:
PrivacyProtect.org
Domain Admin (contact@privacyprotect.org)
P.O. Box 97
Note - All Postal Mails Rejected, visit Privacyprotect.org
Moergestel
null,5066 ZH
NL
Tel. +45.36946676
Creation Date: 04-Mar-2008
Expiration Date: 04-Mar-2009
Domain servers in listed order:
ns12.allwebserver.com
ns11.allwebserver.com
Administrative Contact:
PrivacyProtect.org
Domain Admin (contact@privacyprotect.org)
P.O. Box 97
Note - All Postal Mails Rejected, visit Privacyprotect.org
Moergestel
null,5066 ZH
NL
Tel. +45.36946676
Technical Contact:
PrivacyProtect.org
Domain Admin (contact@privacyprotect.org)
P.O. Box 97
Note - All Postal Mails Rejected, visit Privacyprotect.org
Moergestel
null,5066 ZH
NL
Tel. +45.36946676
Billing Contact:
PrivacyProtect.org
Domain Admin (contact@privacyprotect.org)
P.O. Box 97
Note - All Postal Mails Rejected, visit Privacyprotect.org
Moergestel
null,5066 ZH
NL
Tel. +45.36946676
Status:ACTIVE

Spamming,Exposure of Privacy and Inaccurate Information are the major problems related to WHOIS.

IP Address Location / Geolocation - It is the geographic identification of an IP address of any device,server or website by the process of tracking(geotracking)/tracing and mapping.The exact location of an IP address is retrieved from the WHOIS databse.Geotracking information is not always accurate.
For geolocating just go to Ipmango.

Geo Api - It Gives the Output for the geo information of an IP in XML format.
Just check out the services of Ipmango for more information.

IP Address and DNS Explained.

2008-09-17T19:11:00.002+05:30

Devices in a network are referred to as nodes or hosts.

IP (Internet Protocol) address:-Every electronic device (printers,fax,computer,mobiles,routers,etc.),connected to any particular network has a unique Internet Protocol Address or IP Address.IP addresses are same as the home address or telephone number of any person which is unique.They are the addresses to which the data packets from different servers are send.They are created and managed by the Internet Assigned Numbers Authority(IANA).Anybody can even buy several IP addresses from IANA.
Each IP address is a 32 bit number broken into four (4), eight (8) bit sections(i.e.,it is broken up into four octets). Each section is converted from the binary equivalent to a decimal number. When the IP Address is broken into 4 sections the decimal number ranges from 0 to 255.

Static IP Address :- Static(Permanent) IP Address never changes and is fixed whenever an electronic device connects or disconnects to the Internet.

Dynamic IP Address :- Dynamic IP Address is not static,that is,it changes whenever an electronic device disconnects and connects to the Internet.

STRUCTURE OF AN IP ADDRESS

DNS(Domain Name System/Server) - A service or resource which converts/translates hostnames(domain names,which are easier to remember) into it corresponding IP address.IP address are essential for the communication between devices over the network.IP address is the basis of the whole Internet.When we type www.ipmango.com in the address bar of our browser then the browser contacts the DNS server (mostly provided by our Internet Service Provider) which translates www.ipmango.com into its IP address.Without the IP address of the hostname
(ipmango)the browser will not be able to contact to the host.The DNS server maintains a database of domain names and their corresponding IP address.When it is contacted it searches throughout its database to find the match.If the match is not found it updates its database from some other DNS server on the Internet.The DNS server also has a cache(temporary storage area) for faster access of data as then the server will not have to search through its database.The DNS is quite flexible as multiple IP addresses can be assigned to a single domain which leads
to faster and enhanced surfing.For Example:-google.com has multiple IP addresses which are stored in the DNS server's database and when a browser contacts the DNS server, and a random IP is chosen to contact the hostname(google).To check that which DNS server your computer uses (in windows or linux) just write the command 'nslookup' in command line and hit enter.
NOTE:- DNS lookup translates hostnames into their corresponding IP addresses and Reverse DNS lookup translates IP addresses into their corresponding hostnames.

Subnet Mask ,Netmask and Default Gateway Explained

2008-09-17T15:57:00.002+05:30

Subnet(subnetwork) is a part of a network(devices in a LAN or in a building) that shares a common I address.All the devices whose IP addresses have the same prefix belong to the same subnet.For example, all the devices whose IP addresses starts with 192.168.1 would be a part of the same subnet(255.255.255.0).By knowing the subnet you can easily identify whether the devices are in a particular and same network or not.

Subnet Mask - Just like an ip address a subnet mask also consists of 4 parts each of 8 bits(1 byte) which equals 32 bits(4 bytes).For example:-255.0.0.0 is a subnet mask whose binary is 11111111.00000000.00000000.00000000.

Ip addresses of Class A implicitly uses subnet mask 255.0.0.0.
Ip addresses of Class B implicitly uses subnet mask 255.255.0.0 .
Ip addresses of Class C implicitly uses subnet mask 255.255.255.0.

The binary form of a subnet mask must have its leftmost bits set to 1 and rightmost bits set to 0.
Thus,
Case 1 - 00000000.11111111.11111111.00000000 is an invalid subnet mask but 11111111.11111111.11111111.00000000 is a valid subnet mask.
Case 2 - 11111111.00000000.00000000.11111111 is an invalid subnet mask but 11111111.11111111.11111111.00000000 is a valid subnet mask.

Subnet Mask helps you to identify the Netid and the Hostid by demarcating them.

Calculation of netid and hostid of an ip address of Class B by its subnet mask:-

Calculation of netid and hostid of an ip address of Class C by its subnet mask:-

In both of the above calculations , bitwise AND operation occurs between the IP Address and the Subnet Mask.Bitwise AND operation has the following rules :-
0 AND 0 gives the result 0
0 AND 1 gives the result 0
1 AND 0 gives the result 0
1 AND 1 gives the result 1

Example to understand SubnetId
Ip address - 192.168.1.1
Netid - 192.168
Hostid - 1.1
Now Ip address = netid+subnet id+hostid (since subnetid demarcating the netid and hostid)
Therefore,in the above example if subnet id is alocatted a space of 8 bits then the subnet id will be 1.
Thus,
Netid-192.168
Subnetid - 1
Hostid - 1

Subnet Masking prevents the wastage of IP Addresses.

Netmask - It is a 32-bit value used to divide an IP address into its Netid and Hostid by determining the bits reserved by them and hence the Class of the Ip address.In a netmask one bit is reserved for 0 and another for 255 ,by default.

Default Gateway - It is a device(router) on a network through which a device(source point) on one network can access or send data packets to another device(destination point) on a different network.Technically,a default gateway allows the data packets to pass from one local subnet to other subnets.

Note - The default gateway is not your IP address.

Checking your default gateway in windows is simple.Follow these steps :
1.Click the Start menu and then run. (or simply press the windows button with r)
2.In the box write cmd and hit enter.
3.In the command prompt write the command ipconfig and hit enter again.

The Ip address next to the default gateway is the address of your router(i.e.,that address is the default gateway).

To check your default gateway in Linux try these commands:-

route -n

ip route show

IP Address Versions 4,5 and 6

2008-09-16T21:56:00.002+05:30

IPv4 - First version of IP(Internet Protocol) currently used by nearly all the devices on the internet and so are running short as it comprises only 4 billion IP addresses.Its size is 32 bit.

IPv5 - An experimental version of IP address which never came into existence.

IPv6 - The next generation IP address for future use and replacement for ipv4.Its size is 128 bit and comprises 16 billion IP addresses.

IP Address Structure Explained

2008-09-15T14:53:00.002+05:30

IP Addresses are made up of four parts/can be broken down into four parts.For example 192.168.1.1 can be broken down into 192,168,1 and 1.Each of these represent 8 bits(1 byte).Each of the parts contains numbers ranging from 0-255.
IP Address are divided into five classes which are:-

Netid depicts the network of a device(node) and the Hostid depicts the actual device.

Note :- www.ipmango.com ,which is in the form of alphabets and characters,also represents an IP Address.For example go to command prompt in windows and type 'ping google.com' and hit enter.Then the ip which you will get,write that ip in the address bar of your browser and hit enter and you will reach google.

IP Mango Features.

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1.IP Information ----- IP Address, IP Range, Browser, Operating System, Country, Latitude - Longitude and other details.

2.Client HTTP Headers.

3.Client Side Script.

4.Plugins.

5.MIME Types.

6.IP Whois.

7.Domain Whois.

8.IP to City,ISP etc Lookup.

9.Hash Calculator.

10.Website Analyzer.

11.RealTime BlackList Checker.

12.Free Geo Api - Gives XML Output for the geo information of an IP .

13.Country to IP(Shows the IPs allocated to a country).

14.Geolocation.

15.Regex Tools.

16.Amazing Seo tools.

Position by Keyword - This shows the position of a url in google search results for the given keywords.
Keyword Analyzer - This tool analyzes the top 10 pages in google result for the given keyword. It analyses various attributes of the pages like page rank , size , keyword density in page and title, backlink count etc.
BackLink Analyzer - This shows the number of backlinks for a website and details of first 1000 backlinks.
Sitemap - Crawls all pages on a website. Reports deadlinks.

17.Amazing IP Plotter.

18.Domain Health Checker.

MANY MORES TO BE ADDED.

IP commands of Command line (CLI)in Linux

2008-04-12T19:30:00.003+05:30

Following are the IP Commands for LINUX :-

Display network configurations/settings (including the IP address) - ifconfig

Assign IP Address - ifconfig eth0 192.168.1.6

Show status of ethernet interface eth0 - ethtool eth0

Manually set ethernet interface speed - ethtool --change eth0 autoneg off speed 100 duplex full

Show status of wireless interface eth1 - iwconfig eth1

Manually set wireless interface speed - iwconfig eth1 rate 1Mb/s fixed

List wireless networks in range - iwlist scan

List network interfaces - ip link show

Rename interface eth0 to wan - ip link set dev eth0 name wan

Bring interface eth0 up (or down) - ip link set dev eth0 up

List addresses for interfaces - ip addr show

Add (or del) ip and mask (255.255.255.0) - ip addr add 192.168.1.2/24 brd + dev eth0

List routing table - ip route show

Set default gateway to 192.168.1.1 -

ip route add default via 192.168.1.1

route add default gw 192.168.1.1

Add 20ms latency to loopback device (for testing) - tc qdisc add dev lo root handle 1:0 netem delay 20msec

Remove latency added above - tc qdisc del dev lo root

Lookup DNS ip address for name or vice versa - host ipmango.com

List internet services on a system - netstat -tupl

List active connections to/from system - netstat -tup

Run GUI command on $HOSTNAME as $USER - ssh -f -Y $USER@$HOSTNAME xeyes

Run command on $HOST as $USER - ssh $USER@$HOST command

Copy with permissions to $USER's home directory on $HOST - scp -p -r $USER@$HOST: file dir/

Name of the driver your Ethernet Card is using - # grep eth0 /etc/modules.conf

See Your Public And LAN IP Addresses

IP commands of Command line (CLI) in Dos/Windows

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Following are the IP Commands for Dos/Windows :-

Open Network Connections - control netconnections

Determine Network Connection to a particular destination - ping www.ipmango.com

Determine the Route of a packet through the network - tracert

Display the TCP/IP protocol information - netstat

FOR MORE COMMANDS ON NETSTAT TYPE NETSTAT/HELP IN THE COMMAND LINE.

Manipulates network routing table - route

Display MAC Addresses - arp

Display Name of Computer currently logged into - hostname

Display network settings(including the LAN IP Address.If you are not on LAN then it will show your public IP.) - ipconfig

FOR MORE COMMANDS ON IPCONFIG TYPE IPCONFIG/HELP IN THE COMMAND LINE.

Display paths between two paths - pathping

Display protocol statistics and current TCP/IP connections using NBT(NetBIOS over TCP/IP) - nbtstat

Display the DNS server and its IP address - nslookup

Brief Explaination Of Some Important CommandARP - Address Resolution Protocol translates the Ip address of a device(host) into its MAC/physical address to send a message to it.

PING - A command which sends an ICMP(Internet Control Message Protocol) packet to a host to check whether a host is dead or alive.If the host echoes back the packet then the host is alive else the host is dead.
eg:- ping www.ipmango.com

TRACERT - A command which sends a packet and displays the different systems or servers(in the command line) which the packet passes and thus the route of the packet is known.
eg:- tracert www.ipmango.com

NETSTAT - Displays the currect connections and statistics on the TCP/IP network and there status(whether established or not).

SEE YOUR PUBLIC AND LAN IP Addresses