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What does an IP address look like?

In order to access commercial e-resources, subscribing institutions must provide vendors with their external/public IP address/es as these are used to access the internet.  

The most basic format includes a simple set of 4 blocks of numbers with a minimum of and a maximum of (although neither of these are valid for use for commercial e-resources).

A typical IP address would look like this:

IP addresses can also be shown as a range, for example: or 122.140.201-205.* (* represents 0-255)

IP addresses can also be shown in CIDR format for example: (this represents 122.140.201.*)

For many institutions, the external/public IP address is the address of the proxy server (see Wikipedia entry).

Individual computers which are part of an institutional network may have internal/private IP addresses linking them to the proxy server.  Internal/private IP addresses are not visible on the internet so cannot be used to gain access to commercial e-resources.

The following are examples of internal IP address ranges: – (CIDR = – (CIDR = – (CIDR =