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Revision as of 10:43, 27 April 2021
, 10:43, 27 April 2021→Different forms of connectivity
*Direct optical connection via suppliers will have a terminator in the premises and can offer gigabit speeds or above.
*Direct optical connection via suppliers will have a terminator in the premises and can offer gigabit speeds or above.
*Cable connection links you to your cable company, which provides you with many (though not all) of the same services as a traditional ISP. The speed of transmission over a cable network can vary widely (from quite fast to very slow) based in part on the usage within your neighborhood.
*Cable connection links you to your cable company, which provides you with many (though not all) of the same services as a traditional ISP. The speed of transmission over a cable network can vary widely (from quite fast to very slow) based in part on the usage within your neighborhood.
*4G and soon 5G connection over the mobile network is an option in some rural situtations that are outside the reach of fast physical connections.
*4G and soon 5G connection over the mobile network is an option in some rural situations that are outside the reach of fast physical connections.
*Satellite connectivity: connection either one way (down only, with up over a physical link) or more commonly now two-way. This has had the problem of high latency when used with geo-stationary satellites. New low-earth satellite constellations are becoming available that solve this issue.
'''Dial-up'''
* Where all else fails, connection can be via dialup modems. With dialup connectivity, your server is not usually permanently connected to the Internet. Rather, it connects to your ISP over a phone line using a modem or ISDN adapter . Because your connection to the Internet is not permanent, some of the services on your server cannot be provided to the outside world. For example, having your server host your external company web site would create a problem because whenever your server was not connected to the Internet, the web site would not be available. (However, it could certainly host an intranet web site because the local network would always be connected.)
* Where all else fails, connection can be via dialup modems. With dialup connectivity, your server is not usually permanently connected to the Internet. Rather, it connects to your ISP over a phone line using a modem or ISDN adapter . Because your connection to the Internet is not permanent, some of the services on your server cannot be provided to the outside world. For example, having your server host your external company web site would create a problem because whenever your server was not connected to the Internet, the web site would not be available. (However, it could certainly host an intranet web site because the local network would always be connected.)
====The IP address====
====The IP address====
An IP address is an identifying number assigned to all devices connected to the Internet, and is used in routing information from one device to another. Like your phone number, your IP address enables other people to reach you. In our standard configuration, your ISP only needs to allocate one IP address for your network. It is assigned to your server, which will accept all the Internet data packets intended for your network and distribute them to the appropriate computer - much like an office receptionist is able to accept incoming calls and direct them to the appropriate extension.
An IP address is an identifying number assigned to all devices connected to the Internet, and is used in routing information from one device to another. Like your phone number, your IP address enables other people to reach you. In our standard configuration, your ISP only needs to allocate one IP address for your network. It is assigned to your server, which will accept all the Internet data packets intended for your network and distribute them to the appropriate computer - much like an office receptionist is able to accept incoming calls and direct them to the appropriate extension.
====IPv4 and IPv6 addressing====
Everything in this manual to date refers to IPv4 (IP version 4) addressing. The world is running out -- well, technically-speaking ''has'' run out -- of IPv4 addresses. Various strategies have been adopted by ISPs to obscure and work-round this issue and much of the world is still running on IPv4.
Nonetheless IPv6 addresses will have to be used at some future point, although few ISPs offer direct IP6 connectivity even in 2021. For now, all in this manual concerns IPv4 -- the underlying system is however fully IPv6 capable. Considerable extra work is called for, so as to integrate that support into the system, and this is not a priority for now; eventually of course it will be. If you wish to contribute to this work, please consider volunteering or offering code.
=====Static versus dynamic IP addressing=====
=====Static versus dynamic IP addressing=====
The following three groups of IPv4 addresses are reserved for non-routeable use:
The following three groups of IPv4 addresses are reserved for non-routeable use:
10.0.0.0 - 10.255.255.255 </br>
172.16.0.0 - 172.31.255.255 </br>
192.168.0.0 - 192.168.255.255 </br>
The first and last of these groups are preferred for private networks:
The first and last of these groups are preferred for private networks:
"In August 2012, ARIN began allocating “172” address space to internet service, wireless, and content providers. There have been reports from the community that many network operators are denying access to devices having IP addresses from within the entire 172 /8 range. As a result, any device with a 172.x.x.x IP address may have difficulty reaching some sites on the global Internet." See {https://www.arin.net/reference/research/statistics/address_filters/ ARIN} for more on this.
"In August 2012, ARIN began allocating “172” address space to internet service, wireless, and content providers. There have been reports from the community that many network operators are denying access to devices having IP addresses from within the entire 172 /8 range. As a result, any device with a 172.x.x.x IP address may have difficulty reaching some sites on the global Internet." See [https://www.arin.net/reference/research/statistics/address_filters/ ARIN] for more on this.
{{warning box|If you wish to join two networks via VPN is is IMPERATIVE that they are on different IP blocks, e.g 192.168.100.0 and 192.168.200.0, for trafic to be routed between them.}}
{{warning box|If you wish to join two networks via VPN is is IMPERATIVE that they are on different IP blocks, e.g 192.168.100.0 and 192.168.200.0, for trafic to be routed between them.}}
