GO Software Pty Limited
Map: 27 Tacoma Blvd, Pasadena SA 5042
Phn: 0403-063-991
ABN: 54-008-044-906
Eml: support@gosoftware.com.au
Fax: none
ACN: 008-044-906
Web: www.gosoftware.com.au
Non-Routable IP Address Ranges
There are three ranges of Non-Routable IP Addresses defined for use in internal networks. For an internal network that is
connected to the internet via a router or gateway the addresses MUST be in one of these ranges. IP packets addressed to
addresses in these ranges will NEVER be passed to the internet through the router (unless the router is faulty) and even if they
were your ISP's router would reject them anyway.
To use addresses OUTSIDE of these defined ranges in your internal network you have to either
1. Make sure that your internal network is NEVER connected to the internet
or
2. Apply to acquire these IP addresses as valid Internet IP addresses (eg through your ISP)
Normally, if you wanted to connect a computer to the internet with an IP address OUTSIDE these ranges you still normally do it via
a router or gateway anyway. The gateway then has the externally visible IP address and it forwards all relevant traffic to your
internal machine which will have an IP address INSIDE one of these ranges. Normally you only want a limited number of IP ports
forwarded to your computer anyway - eg
Port 80: Web Server
Ports 20 & 21: FTP Server
Port 25: Email Server
Port 3389: Windows Terminal Server
Non-Routable IP Address Ranges
Reserved IP addresses for private networks
From IP
To IP
Comment
192.168.0.0 192.168.255.255 Best range for most users
172.16.0.0 172.31.255.255 Reasonable range for LARGE networks
10.0.0.0 10.255.255.255 Most flexible range for VERY large networks
The 192.168.x.x range of addresses is usually plenty for even large companies as it still allows you to have up to around 250
separate networks with up to 250 network devices on each network!
Geographic IP Tool
This has nothing to do with routing IP addresses but is interesting anyway. Have a look at http://www.geoiptool.com/ as it will tell
you who owns an IP address ad where it is located.
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