What you're seeing is CIDR notation for IP ranges.
https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing

IMO you don't really need to understand CIDR (I never quite do) as long as
your campus IT office can accurately tell you the range(s) you need to
provide to external vendors.

When you communicate your IP ranges to vendors, some understand and accept
CIDR notation and some do not. At my school (Wake Forest University), we
generally provide our ranges in two ways:

"Please enable access for 152.17.*.* (152.17.0.0/16)."




On Wed, Jul 9, 2025 at 9:14 AM Kristin Oberholtzer <[log in to unmask]>
wrote:

> Our campus IP will soon change, and I am preparing to update our many
> eresource providers. While we can update a fair number by logging into the
> providers' admin portals and manually changing our settings, quite a few
> will need to be handled by direct contacts to the providers.
>
> I am not especially technical and would welcome some basic insights on the
> question below so we can minimize confusion when we contact providers.
>
> The format of the old IP is 1111.11.1.1 and the format of the new IP is
> 222.222.2.222/27
> The first eresource we tested (via updating the admin portal) would not
> accept the /27 portion of the new IP. My colleague's explanation was that
> the /27 suffix denotes how many bytes are available, which is extraneous
> technical info that some systems may need, but is not required. Since our
> old IP does not have such a suffix, and it was rejected in our testing, I
> am inclined to omit the /27 when we contact providers. In nontechnical
> terms please, do you advise including or excluding the /27 suffix?
>
> Thank you!
> Kristin
> Franklin & Marshall College Library
>