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How to enter IP ranges when IT tells you something weird

It sometimes comes up that when you ask your IT people what your IP address or range is they give you a more technical answer than you were expecting such as, or worse something that looks like 2001:0db8:85a3:0000:0000:::7334.

This page will cover what you need to know so you can pop the right numbers into OpenAthens, e.g. for self registration.

If it starts with 192.168.x.x or with 10.x.x.x or any of 172.16.x.x through 172.31.x.x

These are called private address spaces and they're reserved for internal network traffic. They're not the IP address that the rest of the internet can see you at and you'll need to go back to your IT team and clarify that you need the externally facing IP address or range you would appear at to a service.

If it looks anything like

This format with a slash in it is called CIDR notation and the key thing to know is that the /24 is describing how much of the address is fixed... in a way that makes perfect sense to network people. Each chunk is called an 'octet', which is a reference to it being 8 bits of data (numbers 0 though 255). In this case the /24 means the first 24 bits are fixed (24 / 8 = 3 chunks) and the whole of the last chunk could be anything. This would be entered as either:

  • 123.123.123.*

If it said /16 then the first two chunks (16 bits) are fixed and the last two are wild:

  • 123.123.*.*
  • 123.123.0-255.0-255

The other numbers are... unlikely to come up but if they do there are online tools that will translate "CIDR to IP range"

If it's got lots of colons in it

E.g. something like 2001:0db8:85a3:0000:0000:::7334

This is an IPV6 address and we don't yet support that. If they've not also given you something that has dots in it, get back to them and tell them you need "the IPV4 range"

See also:

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