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For security reasons; because each end of a virtual private tunnel on a public network with a firewall/router/VPN
software, is encrypted. |
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Both the data and the IP address at each end are encrypted and this is
called tunneling. |
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When we lease public WAN (wide area network). Because it's too expencive to
have our own network with our own cables laid out around the world, it's
easier and cheaper to lease a line and use firewall- or router-based VPN. |
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For home offices; when employees want to log into the office through an ISP
(internet Service Provider) with a fast internet line (1024 or 2048 kbps
compared to a 56 kbps modem through a telephone line) you can use VPN software
on the home computer. |
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Replaces modem pools for telephone lines where you have to call the office
number to get on the internet or intranet. Phone lines have lower speed than
cable and are expencive to maintain. |
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With encryption you need authentication as well, VPN solutions use
standards like LDAP (lightweight directory access protocol). |
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A safe VPN tunnel needs:
#1: Confidetiality: Your data can not be read by others
(encryption) #2: Your data is not altered by others (hashing)
#3.: Verify
Data Integrity: Your data can
prove that it comes from you only (authentication) |