Introduction and Overview

IP address space is a limited resource that is being depleted at a significant rate. Several registries have been established around the world to regulate the usage of these addresses. These registries are governed by the Internet Community. In the United States, we are governed by the American Registry for Internet Numbers (ARIN).

ARIN typically only provides addresses in /19 blocks (8192 individual addresses, or 32 Class Cs) or more, most companies need to contact their upstream provider, in this case Citynet. However, ARIN will provide a /20 (16 Class Cs) to an organization that is multi-homed. In order for Citynet to acquire address space from ARIN, we must follow their guidelines for IP address assignments and allocations and must enforce efficient utilization of IP addresses. This means that our customers must justify their IP needs to us in detail and according to ARIN's guidelines for effective usage.

ARIN's policies can be found on their website. Links to the ARIN website are at the bottom of the page.

All information disclosed to Citynet during this process is confidential, with a single exception, we are required to provide ARIN with the same information you provide to us in order to justify our need for additional address space.

All numbers must be accounted for, and each address block must be reassigned via SWIP, RWHOIS or internal databases. At this time, RWHOIS is the preferred reassignment method available for Citynet's address blocks. Large address consumers will also be required to maintain, and provide upon request, a database of how addresses are assigned internally.


Guidelines and Rules

• Citynet will not provide aggregate allocations larger than a /21 (eight "Class C" netblocks). Applications for address allocations larger than a /21 must be made directly to ARIN.
• Citynet will not provide allocations or assignments to customers who already have a direct allocation from ARIN.
• A usage figure of 80 percent must be achieved within 90 days after allocation/assignment, or the addresses will be withdrawn. (Eighty percent usage is based on SWIP records and a simple ICMP scan run against all assigned net blocks.)
• Customers must maintain proper reverse DNS records for all assigned or allocated addresses. Contact ipadmin@citynet.net with any questions.
• Customers will not be given address space for administrative convenience.
• Citynet cannot guarantee the assignment of contiguous netblocks.
• We reserve right to change customer assignments/allocations as necessary.

ARIN Links
ARIN - Official Website