Friday, October 14, 2005
Thursday, October 13, 2005
Religions and God
Although this is true that religion is the integral part of our life or we can say it as human existence. But while chatting with one of my friend I got to know some thing called Taoism and then to capitalized my time over here in the project I started reading books and article related to religion apart from technical books and article (Its my Hobby). Some of the research work which I am able to explore describes different religions in term of God or Baghwan or Iswar or Allaha etc what ever u call it i will call it Almighty (Not of movie :) ) except for some of them, after all exception are every where.
Human psychology insist every human being to accept the existence of the creator, unless he has been conditioned to believe the contrary . I am ready to bet on that 97% of the human in the world believe in the existence of creator be it scientist, astronaut , doctor , computer professional or be a psycho too. Hence I can conclude that believing in god requires no reason or proofs while rejection of god does. I am also trying to do the depth study of religions one by one but here again if almighty will allow me and support to do it. :)
Some of the research papers broadly categorized the religions of this planet into two categories .
Semitic
Non-Semitic
Here Semitic word is derived from the name of one of the character of holy Bible Shem considered to be son of Prophet Noah. Descendents of Shem are known as Semites. Hence the Semitic religion are the religions that originated among Jews, Arabs, Assyrians, Phoenicians, etc. Major religion in this category are Judaism, Christianity, Islam,
Also known as prophetic religion that believe in divine guidance given by prophet of God.
Non -Semitic religions are further sub divided in to two more category
Named on the community or race consist of powerful group of Indo-European speaking people that spread through Iran and Northern India in the first half of the second Millennium BC (2000 to 1500 BC). Almost all of the major Aryan religions are non-prophetic religions.
It is further divided into two major categories
Non-Aryan
Religions have diverse origins. Like Confucianism and Taoism are of Chinese origin while Shintoism is of Japanese origin and do not have a concept of God. Some critics refer them as ethical system rather than as religions.
Confucianism moral and religious system of China is also considered to be agnostic religion and do not comment on God.
Taoism refers both to a Chinese system of thought and to one of the four major religions of China and do not have a concept of God. Tao means the way or path. Taoism has had a significant influence world-wide: in many Western societies it can be seen in acupuncture, herbalist, holistic medicine, meditation, martial arts, Feng Shui and Tai Chi .
Aryan Vedic :
Hinduism is an assortment of religious beliefs, most of whom are based on Vedas and Upanishads. It is commonly perceived as a polytheistic religion. Some believe in the system of three Super Powers some believe in the existence of 33crore i.e. 330 million Gods. However learned Hindus who are well versed with their scriptures insist that a Hindu should believe in only one God. But then what is 330million ?
Its very simple as per the Hindu believes every thing is god (God is present in) be it tree, sun, moon, animals or even U and me . And as per believe their is 330 million creatures are in planet hence if every thing is god then 330 million gods are their.
Second believe of 3 super powers are considered to be the attributes of god; Creator, Sustainer and Destroyer (Brahma, Vishnu & Mahesh), originated from the null (sunya or Zero or Null ) called "OM" (its nothing but only a sound ) means god attributes originated from sound. ( In scientific term I can explain it with an example of nucleus of an atom. So their is different attributes of atom its an creator , its an sustainer its and destroyer too but its self existence is nill ie Zero its an totally different matter of fact, what it creates, what it sustain and what it destroy.) That's why in yoga this sound has a very special significance. I don't know how you will take it. But its an believe of millions of Hindus and mine too. Their is thousand of other believes too but most of them at last conclude in these two believes only. Hinduism believe in the doctrine of incarnation (Avtars).
Aryan Non Vedic:
Sikhism: Its an non Vedic religion but considered to be the offshoot or branch of Hinduism founded by Guru Nanak at the end of the 15th Century originated in the area of Pakistan and northwest India called Punjab meaning the land of 5 rivers. GuruNanak was born in warrior cast of Hindu family but was very strongly influenced by Islam. Sikh word is derived from the word Sisya meaning follower. Its an religion of 10 Gurus (Teachers). The sacred book of Sikhism is Sri Guru Granth also called Adi Granth Sahib. In this religious believe their is one supreme god who is in the unmanifest form called "OM" and having several attributes. While Sikhism does not believe in incarnation means god does not incarnate himself in what is known as avatar. Also idol worship is strongly against this religion.
Buddhism is considered to be agnostic religion and do not comment on God . In the religion its neither confirm nor deny the existence of God. But I know most of the Buddhism followers believe in existence of almighty. This religion and philosophy founded in India c.525 B.C. by Siddhartha Gautama, called the Buddha. There are over 300 million Buddhists worldwide. One of the great world religions, it is divided into two main schools: the Theravada or Hinayana in Sri Lanka and SE Asia, and the Mahayana in China, Mongolia, Korea, and Japan. A third school, the Vajrayana, has a long tradition in Tibet and Japan. Buddhism has largely disappeared from its country of origin, India.
Jainism is considered to atheistic religion which do not believe in the existence of God. Being an ascetic religion of India, that teaches the immortality and transmigration of the soul and denies the existence of a perfect or supreme being. Arose in the 6th cent. B.C. as protests against the overdeveloped ritualism of Hinduism , particularly its sacrificial cults, and the authority of the Veda. Jain tradition teaches that a succession of 24 tirthankaras (saints) originated the religion. The last, Vardhamana, called Mahavira [the great hero] and Jina [the victor], seems to be historical. He preached a rigid asceticism and solicitude for all life as a means of escaping the cycle of rebirth, or the transmigration of soul. Thus released from the rule of karma, the total consequences of past acts, the soul attains nirvana , and hence salvation. Mahavira organized a brotherhood of monks, who took vows of celibacy, nudity, self-mortification, and fasting. Since the 1st cent. A.D., when a schism developed over the issue of nudity, there have been two great divisions of Jains, the Digambaras [space-clothed, i.e., naked] and the Svetambaras [white-clothed]. Jainists, then as now, accumulate merit through charity, through good works, and in occasional monastic retreat.
Zoroastrianism (Parsiism) is an ancient Aryan religion originated in Persia more that 2500 years ago. Though it has relatively few adherents, less that one hundred and thirty thousand in the whole world, The Iranian prophet Zoroaster was the founder of Zoroastrianism. The scared scripture of parsis is the Dasatir and Avesta.
Semitic
Judaism is one of the major Semitic religions. Its followers are known as Jews and they believe in the prophetic mission of Prophet Moses. That's what I am able to explore so far.
Christianity and Islam: They are almost same only way of seeing things different . Both religion believe in the one supreme power . Both of the religions believes in the existence of Jesus. Difference is that in Islam its believed that Jesus was one of the mightiest messenger of god while Christian believes in divinity of Jesus. In Islam it is a believe that Holy Quran has word of God revealed to Prophet Mohammed. Also Idiol worship is strictly prohibated. As per islamic belives every thing is of god's be it tree, animals, human, sun, and moon.
Human psychology insist every human being to accept the existence of the creator, unless he has been conditioned to believe the contrary . I am ready to bet on that 97% of the human in the world believe in the existence of creator be it scientist, astronaut , doctor , computer professional or be a psycho too. Hence I can conclude that believing in god requires no reason or proofs while rejection of god does. I am also trying to do the depth study of religions one by one but here again if almighty will allow me and support to do it. :)
Some of the research papers broadly categorized the religions of this planet into two categories .
Semitic
Non-Semitic
Here Semitic word is derived from the name of one of the character of holy Bible Shem considered to be son of Prophet Noah. Descendents of Shem are known as Semites. Hence the Semitic religion are the religions that originated among Jews, Arabs, Assyrians, Phoenicians, etc. Major religion in this category are Judaism, Christianity, Islam,
Also known as prophetic religion that believe in divine guidance given by prophet of God.
Non -Semitic religions are further sub divided in to two more category
- Aryans
- Non-Aryans
Named on the community or race consist of powerful group of Indo-European speaking people that spread through Iran and Northern India in the first half of the second Millennium BC (2000 to 1500 BC). Almost all of the major Aryan religions are non-prophetic religions.
It is further divided into two major categories
- Vedic
- Non-Vedic
Non-Aryan
Religions have diverse origins. Like Confucianism and Taoism are of Chinese origin while Shintoism is of Japanese origin and do not have a concept of God. Some critics refer them as ethical system rather than as religions.
Confucianism moral and religious system of China is also considered to be agnostic religion and do not comment on God.
Taoism refers both to a Chinese system of thought and to one of the four major religions of China and do not have a concept of God. Tao means the way or path. Taoism has had a significant influence world-wide: in many Western societies it can be seen in acupuncture, herbalist, holistic medicine, meditation, martial arts, Feng Shui and Tai Chi .
Aryan Vedic :
Hinduism is an assortment of religious beliefs, most of whom are based on Vedas and Upanishads. It is commonly perceived as a polytheistic religion. Some believe in the system of three Super Powers some believe in the existence of 33crore i.e. 330 million Gods. However learned Hindus who are well versed with their scriptures insist that a Hindu should believe in only one God. But then what is 330million ?
Its very simple as per the Hindu believes every thing is god (God is present in) be it tree, sun, moon, animals or even U and me . And as per believe their is 330 million creatures are in planet hence if every thing is god then 330 million gods are their.
Second believe of 3 super powers are considered to be the attributes of god; Creator, Sustainer and Destroyer (Brahma, Vishnu & Mahesh), originated from the null (sunya or Zero or Null ) called "OM" (its nothing but only a sound ) means god attributes originated from sound. ( In scientific term I can explain it with an example of nucleus of an atom. So their is different attributes of atom its an creator , its an sustainer its and destroyer too but its self existence is nill ie Zero its an totally different matter of fact, what it creates, what it sustain and what it destroy.) That's why in yoga this sound has a very special significance. I don't know how you will take it. But its an believe of millions of Hindus and mine too. Their is thousand of other believes too but most of them at last conclude in these two believes only. Hinduism believe in the doctrine of incarnation (Avtars).
Aryan Non Vedic:
Sikhism: Its an non Vedic religion but considered to be the offshoot or branch of Hinduism founded by Guru Nanak at the end of the 15th Century originated in the area of Pakistan and northwest India called Punjab meaning the land of 5 rivers. GuruNanak was born in warrior cast of Hindu family but was very strongly influenced by Islam. Sikh word is derived from the word Sisya meaning follower. Its an religion of 10 Gurus (Teachers). The sacred book of Sikhism is Sri Guru Granth also called Adi Granth Sahib. In this religious believe their is one supreme god who is in the unmanifest form called "OM" and having several attributes. While Sikhism does not believe in incarnation means god does not incarnate himself in what is known as avatar. Also idol worship is strongly against this religion.
Buddhism is considered to be agnostic religion and do not comment on God . In the religion its neither confirm nor deny the existence of God. But I know most of the Buddhism followers believe in existence of almighty. This religion and philosophy founded in India c.525 B.C. by Siddhartha Gautama, called the Buddha. There are over 300 million Buddhists worldwide. One of the great world religions, it is divided into two main schools: the Theravada or Hinayana in Sri Lanka and SE Asia, and the Mahayana in China, Mongolia, Korea, and Japan. A third school, the Vajrayana, has a long tradition in Tibet and Japan. Buddhism has largely disappeared from its country of origin, India.
Jainism is considered to atheistic religion which do not believe in the existence of God. Being an ascetic religion of India, that teaches the immortality and transmigration of the soul and denies the existence of a perfect or supreme being. Arose in the 6th cent. B.C. as protests against the overdeveloped ritualism of Hinduism , particularly its sacrificial cults, and the authority of the Veda. Jain tradition teaches that a succession of 24 tirthankaras (saints) originated the religion. The last, Vardhamana, called Mahavira [the great hero] and Jina [the victor], seems to be historical. He preached a rigid asceticism and solicitude for all life as a means of escaping the cycle of rebirth, or the transmigration of soul. Thus released from the rule of karma, the total consequences of past acts, the soul attains nirvana , and hence salvation. Mahavira organized a brotherhood of monks, who took vows of celibacy, nudity, self-mortification, and fasting. Since the 1st cent. A.D., when a schism developed over the issue of nudity, there have been two great divisions of Jains, the Digambaras [space-clothed, i.e., naked] and the Svetambaras [white-clothed]. Jainists, then as now, accumulate merit through charity, through good works, and in occasional monastic retreat.
Zoroastrianism (Parsiism) is an ancient Aryan religion originated in Persia more that 2500 years ago. Though it has relatively few adherents, less that one hundred and thirty thousand in the whole world, The Iranian prophet Zoroaster was the founder of Zoroastrianism. The scared scripture of parsis is the Dasatir and Avesta.
Semitic
Judaism is one of the major Semitic religions. Its followers are known as Jews and they believe in the prophetic mission of Prophet Moses. That's what I am able to explore so far.
Christianity and Islam: They are almost same only way of seeing things different . Both religion believe in the one supreme power . Both of the religions believes in the existence of Jesus. Difference is that in Islam its believed that Jesus was one of the mightiest messenger of god while Christian believes in divinity of Jesus. In Islam it is a believe that Holy Quran has word of God revealed to Prophet Mohammed. Also Idiol worship is strictly prohibated. As per islamic belives every thing is of god's be it tree, animals, human, sun, and moon.
Monday, October 10, 2005
Configure a Win2K DNS server to forward external requests
Jun 13, 2002
This experience is very interesting for me with my first real time encounter for Win2000 Network That’s why I like to share my this experience with all of you . Firstly I Introduce the concept & Then describe how to do this. You know how DNS is supposed to work. You type http://www.keekar.com into your browser, your DNS server resolves the name into an IP address, and then your browser connects to the Web page at that address and displays it. However, after you set up Windows 2000 domain controllers, Active Directory, and a Windows 2000 DNS server, you may find that your systems are unable to resolve any Web addresses for resources outside your local network.
This problem occurs because Windows 2000 can sometimes configure its DNS server to act as a root server. As a root server, the DNS server will resolve only addresses that it has DNS records for (usually only local resources). I’m going to show you why this happens and how to fix it.
What's the problem?
In a Windows 2000 environment, DNS fills two roles. First, Windows 2000’s DNS can provide traditional Internet name resolution for clients on your network that need to access Internet resources. Second, Windows 2000’s DNS can provide access to Active Directory and local network resources.
When you first install DNS and Active Directory on your network, Windows 2000’s Setup program can cause these two roles to come into conflict with each other. Setup can accidentally configure DNS to resolve Active Directory resources but not allow clients to access Internet-based DNS servers.
When Setup runs, it checks your network for other DNS servers. If it doesn't’t find any, Setup assumes that it’s the only DNS server on the planet and sets itself up as a root server. By definition, root servers are authoritative. Basically, they are DNS know-it-alls that don’t require help from other DNS servers.
In a network that’s not connected to the Internet, having your main DNS server configured as a root server isn’t a problem. Because there aren’t any external addresses to worry about, the root server indeed knows all there is to know about addresses on your network. However, things become complicated when you connect your network to the Internet. At that point, your internal DNS server can’t know the address for every Internet resource, so it requires help from external DNS servers.
If Setup has configured your DNS server as a root server, the DNS server won’t look for help from external DNS servers. As a matter of fact, if you try to configure forwarders or root hints on a Windows 2000 DNS root server, it will refuse to accept the information.
Tearing it out by the root
So what do you do to allow your internal Windows 2000 DNS server to forward queries to external DNS servers for addresses it doesn’t know? You manually administer an attitude adjustment to your DNS server to make it realize that there are other DNS servers it should refer to, essentially removing the DNS server’s root server configuration.
To do so, click Start | Programs | Administrative Tools | DNS. This will start the DNS Management Console. Expand DNS Server object in the left pane. Expand the Forward Lookup Zones folder. Select the zone folder that is marked with a period, right-click on it, and select Delete. Delete ting the root "." forward zone, to convince your DNS server that there are at least 13 more knowledgeable name servers than itself. In addition, you will need to provide your machine with a list of those wise root name servers. This can be accomplished in two ways:
· By adding forwarders (usually your ISP's name servers);
· By adding root hints, or both. You do this in the mmc (Right-click your machine name>Properties>Forwarders: Check "enable forwarders" & enter their IP addresses (You can usually get a list of your ISP's name servers by using whois).
If you’re using Active Directory Integrated Zones, the DNS MMC will display a dialog box informing you that when you delete the zone, the MMC will also delete the zone from Active Directory and any DNS server that references Active Directory. Click Yes to remove the zone from both Active Directory and the DNS server.
Setting up forwarders
After you restart your Windows server, you can configure DNS to forward to other DNS servers. Start the DNS MMC again, right-click on your DNS server, and select Properties. When the Properties window for the server appears, click the Forwarders tab. Select the Enable Forwarders check box.
If this check box is grayed out, your DNS server is still configured as a root server. Check to make sure that you’ve selected the right DNS server and properly removed the root zone folder as mentioned above.
In the IP address field, enter the DNS servers you want to forward to. You’ll need to enter the IP address of each server one at a time, clicking Add after each one. When you have finished, click OK.
Going forward
Once you remove the DNS server’s root capability and configure forwarders on your DNS server, your workstations will be able to access both internal and external network resources. By doing this, you can save yourself the headache of entering multiple DNS addresses on client workstations (or setting them up in DHCP). Simply direct client requests to your Windows 2000 DNS server, and it will handle the requests that it can and forward all other requests to the external DNS servers.
This experience is very interesting for me with my first real time encounter for Win2000 Network That’s why I like to share my this experience with all of you . Firstly I Introduce the concept & Then describe how to do this. You know how DNS is supposed to work. You type http://www.keekar.com into your browser, your DNS server resolves the name into an IP address, and then your browser connects to the Web page at that address and displays it. However, after you set up Windows 2000 domain controllers, Active Directory, and a Windows 2000 DNS server, you may find that your systems are unable to resolve any Web addresses for resources outside your local network.
This problem occurs because Windows 2000 can sometimes configure its DNS server to act as a root server. As a root server, the DNS server will resolve only addresses that it has DNS records for (usually only local resources). I’m going to show you why this happens and how to fix it.
What's the problem?
In a Windows 2000 environment, DNS fills two roles. First, Windows 2000’s DNS can provide traditional Internet name resolution for clients on your network that need to access Internet resources. Second, Windows 2000’s DNS can provide access to Active Directory and local network resources.
When you first install DNS and Active Directory on your network, Windows 2000’s Setup program can cause these two roles to come into conflict with each other. Setup can accidentally configure DNS to resolve Active Directory resources but not allow clients to access Internet-based DNS servers.
When Setup runs, it checks your network for other DNS servers. If it doesn't’t find any, Setup assumes that it’s the only DNS server on the planet and sets itself up as a root server. By definition, root servers are authoritative. Basically, they are DNS know-it-alls that don’t require help from other DNS servers.
In a network that’s not connected to the Internet, having your main DNS server configured as a root server isn’t a problem. Because there aren’t any external addresses to worry about, the root server indeed knows all there is to know about addresses on your network. However, things become complicated when you connect your network to the Internet. At that point, your internal DNS server can’t know the address for every Internet resource, so it requires help from external DNS servers.
If Setup has configured your DNS server as a root server, the DNS server won’t look for help from external DNS servers. As a matter of fact, if you try to configure forwarders or root hints on a Windows 2000 DNS root server, it will refuse to accept the information.
Tearing it out by the root
So what do you do to allow your internal Windows 2000 DNS server to forward queries to external DNS servers for addresses it doesn’t know? You manually administer an attitude adjustment to your DNS server to make it realize that there are other DNS servers it should refer to, essentially removing the DNS server’s root server configuration.
To do so, click Start | Programs | Administrative Tools | DNS. This will start the DNS Management Console. Expand DNS Server object in the left pane. Expand the Forward Lookup Zones folder. Select the zone folder that is marked with a period, right-click on it, and select Delete. Delete ting the root "." forward zone, to convince your DNS server that there are at least 13 more knowledgeable name servers than itself. In addition, you will need to provide your machine with a list of those wise root name servers. This can be accomplished in two ways:
· By adding forwarders (usually your ISP's name servers);
· By adding root hints, or both. You do this in the mmc (Right-click your machine name>Properties>Forwarders: Check "enable forwarders" & enter their IP addresses (You can usually get a list of your ISP's name servers by using whois).
If you’re using Active Directory Integrated Zones, the DNS MMC will display a dialog box informing you that when you delete the zone, the MMC will also delete the zone from Active Directory and any DNS server that references Active Directory. Click Yes to remove the zone from both Active Directory and the DNS server.
Setting up forwarders
After you restart your Windows server, you can configure DNS to forward to other DNS servers. Start the DNS MMC again, right-click on your DNS server, and select Properties. When the Properties window for the server appears, click the Forwarders tab. Select the Enable Forwarders check box.
If this check box is grayed out, your DNS server is still configured as a root server. Check to make sure that you’ve selected the right DNS server and properly removed the root zone folder as mentioned above.
In the IP address field, enter the DNS servers you want to forward to. You’ll need to enter the IP address of each server one at a time, clicking Add after each one. When you have finished, click OK.
Going forward
Once you remove the DNS server’s root capability and configure forwarders on your DNS server, your workstations will be able to access both internal and external network resources. By doing this, you can save yourself the headache of entering multiple DNS addresses on client workstations (or setting them up in DHCP). Simply direct client requests to your Windows 2000 DNS server, and it will handle the requests that it can and forward all other requests to the external DNS servers.
Sunday, October 02, 2005
Using ssh in place of rsh.
Before we could start on this first take a look how authentication is worked in ssh . Authentication varies depending upon the version of protocol.
SSH protocol version 1
The first authentication method is the rhosts or hosts.equiv method combined with RSA-based host authentication. If the machine the user logs in from is listed in /etc/hosts.equiv or /etc/shosts.equiv on the remote machine, and the user names are the same on both sides, or if the files ~/.rhosts or ~/.shosts exist in the user's home directory on the remote machine and contain a line containing the name of the client machine and the name of the user on that machine, the user is considered for log in. Additionally, if the server can verify the client's host key (see /etc/ssh_known_hosts and ~/.ssh/known_hosts in the FILES section), only then is login permitted. This authentication method closes security holes due to IP spoofing, DNS spoofing and routing spoofing. [Note to the administrator: /etc/hosts.equiv, ~/.rhosts, and the rlogin/rsh protocol in general, are inherently insecure and should be disabled if security is desired.] I am call this mechanishm as server authentication mechanism.
As a second authentication method, ssh supports RSA based authenticationThe scheme is based on public-key cryptography: there are cryptosystems.
SSH protocol version 2
When a user connects using protocol version 2, similar authenticationmethods are available. Using the default values for PreferredAuthentications, the client will try to authenticate first using the hostbased method; if this method fails, public key authentication is attempted, and finally if this method fails, keyboard-interactive and password authentication are tried.
The public key method is similar to RSA authentication described in the previous section and allows the RSA or DSA algorithm to be used: The client uses his private key ~/.ssh/id_dsa or ~/.ssh/id_rsa, to sign the session identifier and sends the result to the server. The server checks whether the matching public key is listed in ~/.ssh/authorized_keys and grants access if both the key is found and the signature is correct. The session identifier is derived from a shared Diffie-Hellman value and is only known to the client and the server.
If public key authentication fails or is not available, a password can be sent encrypted to the remote host to prove the user's identity.
Lets go little bit more depth on Server authentication because I am using this.
ssh automatically maintains and checks a database containing identifications for all hosts it has ever been used with. Host keys are stored in ~/.ssh/known_hosts in the user's home directory. Additionally, the file /etc/ssh_known_hosts is automatically checked for known hosts. Any new hosts are automatically added to the user's file. If a host's identification ever changes, ssh warns about this and disables password authentication to prevent a trojan horse from getting the user's password. Another purpose of this mechanism is to prevent man-in-the-middle attacks which could otherwise be used to circumvent the encryption.The StrictHostKeyChecking option can be used to prevent logins to machines whose host key is not known or has changed.
So once every thing is set use following command.
# ssh -t \server\ \command
Ex.
# ssh -t server2.keekar.com ls -ltr
Output will come on the calling screen not on remote screen. Also their is no login shell is allocated means once the command finished it itself colsed.
SSH protocol version 1
The first authentication method is the rhosts or hosts.equiv method combined with RSA-based host authentication. If the machine the user logs in from is listed in /etc/hosts.equiv or /etc/shosts.equiv on the remote machine, and the user names are the same on both sides, or if the files ~/.rhosts or ~/.shosts exist in the user's home directory on the remote machine and contain a line containing the name of the client machine and the name of the user on that machine, the user is considered for log in. Additionally, if the server can verify the client's host key (see /etc/ssh_known_hosts and ~/.ssh/known_hosts in the FILES section), only then is login permitted. This authentication method closes security holes due to IP spoofing, DNS spoofing and routing spoofing. [Note to the administrator: /etc/hosts.equiv, ~/.rhosts, and the rlogin/rsh protocol in general, are inherently insecure and should be disabled if security is desired.] I am call this mechanishm as server authentication mechanism.
As a second authentication method, ssh supports RSA based authenticationThe scheme is based on public-key cryptography: there are cryptosystems.
SSH protocol version 2
When a user connects using protocol version 2, similar authenticationmethods are available. Using the default values for PreferredAuthentications, the client will try to authenticate first using the hostbased method; if this method fails, public key authentication is attempted, and finally if this method fails, keyboard-interactive and password authentication are tried.
The public key method is similar to RSA authentication described in the previous section and allows the RSA or DSA algorithm to be used: The client uses his private key ~/.ssh/id_dsa or ~/.ssh/id_rsa, to sign the session identifier and sends the result to the server. The server checks whether the matching public key is listed in ~/.ssh/authorized_keys and grants access if both the key is found and the signature is correct. The session identifier is derived from a shared Diffie-Hellman value and is only known to the client and the server.
If public key authentication fails or is not available, a password can be sent encrypted to the remote host to prove the user's identity.
Lets go little bit more depth on Server authentication because I am using this.
ssh automatically maintains and checks a database containing identifications for all hosts it has ever been used with. Host keys are stored in ~/.ssh/known_hosts in the user's home directory. Additionally, the file /etc/ssh_known_hosts is automatically checked for known hosts. Any new hosts are automatically added to the user's file. If a host's identification ever changes, ssh warns about this and disables password authentication to prevent a trojan horse from getting the user's password. Another purpose of this mechanism is to prevent man-in-the-middle attacks which could otherwise be used to circumvent the encryption.The StrictHostKeyChecking option can be used to prevent logins to machines whose host key is not known or has changed.
So once every thing is set use following command.
# ssh -t \server\ \command
Ex.
# ssh -t server2.keekar.com ls -ltr
Output will come on the calling screen not on remote screen. Also their is no login shell is allocated means once the command finished it itself colsed.
IT export of India
One of my college always state that the India software export is only 2% of its all export and crib that Indian government is not doing any thing for its other export (agriculture according to him) which are the core of export. His cribbing and criticism enforced me to collect some vital statistics and know the truth. Why in country so much hype for software export sorry its better to say IT export . This small research help me to collect some of the information which are mind blowing . Like to share some of these information with u people so that some misconceptions and elegation will be removed. I agree the statistics are not every thing but still it is some thing. Proof is below.
Starting from Union budget 2003-2004 section 1.44 India continues to make progress on export-oriented production in electronics and computer technology. Software exports have grown at a compound growth rate of over 50 percent per year for the last five years. (unfortunatly our gov is not able to understand that its not software export but its and combined IT export hopefully they are able to correct it in next budget) So if government is concentrating more in this sector whats the harm . It doesnt mean that putting so much efforts in this sector makes them sleep for other sector.
As per the report published on 4th July 2005 India's merchandise exports have almost doubled in the last three years to $80 billion, and exports of software/IT-enabled services have almost tripled to $17.2 billion. which shows that the software/IT-enabled export is not 2% while its approx 21%. Might be he has some wrong data or some calculation mistake. It might be 2% once upon a time. Some other statistics which I am able to consolidate are as.
As per one of the prediction report published by McKinsey
India started exporting software in 1983 is expected to touch an envious $ 50 billion figure in 2008. India whose export earnings from all sources totalled $ 36 billion till recently will be able to boost its total exports to $ 260 billion in 2008, 35 per cent of it from the IT related exports.
Other key findings of this report are:
- Software & Services will contribute over 7.5 % of the overall GDP growth of India
- Total annual turnover of IT Industry is $ 87 Billion (Internal + export)
- IT Exports will account for 35% of the total exports from India
- Potential for 2.2 million jobs in IT by 2008
- IT industry will attract Foreign Direct Investment (FDI) of U.S. $ 4-5 billion
- Market capitalization of IT shares will be around U.S. $ 225 billion
India started IT related exports as early as 1984, the Indian IT industry remained in red till 1993. The first and only one multinational company, Texas Instruments, came to India in 1986. The year 1993 could be called a turning point for the Indian IT industry when the software exports crossed the $ 330 million figure, over six-fold that of $ 52 million in 1987. It was also the year when the US MNCs flocked to India in gangs to reap the profit.
A very interesting statistics is present in BREAK-UP OF PROJECTED $ 87 BILLION IT INDUSTRY
- IT Services -$ 39 Billion- 45%
- Software Products -$20 Billion- 23%
- IT Enabled Services (BPO) -$ 19 Billion- 21%
- e-Business -$ 10 Billion -11%
So what would you think so called software developers and software consultants. 80% of us who is working in software usually see IT Enabled Services (BPO) with some other angle which is competeting while IT Services (Support centers or maintenance project ) will be the leading the export economy.
This is the fact that fastest-growing export sector is the outsourcing of business services called BPO (business process outsourcing) or ITES (information technology enabled services). These span a huge range of services from simple call-centres to engineering and R&D services. They are growing so rapidly that one day they will surely overhaul software exports. In 2004-05, computer software exports rose 30.4 %, but service outsourcing exports rose even faster by 44.4 %.
Indian software giants like TCS, Infosys and Wipro are India's biggest exporters. Yet, foreign companies now account for 30 per cent to 35 per cent of software exports. Every big name in the world has opened an Indian unit, from Microsoft to Oracle to SAP. Here again, what look like Indian exports are also the internal trade of MNCs.
What is not so well known is that two-thirds of our outsourcing exports come from captive Indian units of multinational corporations. The entire industry was kick-started by General Electric, and others followed. So, India's most dynamic export sector is not Indian at all but foreign-owned. In official economic terms, such service exports are Indian exports. But in pure business terms, they are the internal trade of MNCs.
This shows that globalisation is not a zero sum game, in which the gains of one side are the losses of the other side. Both sides gain. There are some short-term losers in the US whose jobs travel to India. But US living standards rise only because workers are constantly forced out of lower-productivity jobs into higher-productivity ones. Every year, the US destroys 32 million jobs and creates 32.5 million jobs. The net result is a richer, more productive USA.
Subscribe to:
Posts (Atom)