At present it is only possible to add single IP addresses to ILS-DI:AuthorizedIPs. This is difficult to manage if the source resource has a large pool of public addresses that can be used to connect. Adding CIDR notation ability to ILS-DI:AuthorizedIPs would help to manage this problem.
I think this is a possible duplicate to bug 24537 - marking as such, please undo if incorrect.
*** This bug has been marked as a duplicate of bug 24537 ***
Yeah this is definitely a duplicate. Barry, feel free to sign off https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=24537 :D