IP Address Management – What do you use?

Terry Slattery
Principal Architect

Zeus Karravala, an analyst at The Yankee Group, recently wrote a blog about It’s Time for Companies to Take IP Address Management Seriously. Like Zeus, I find that spreadsheets are the most common tool that NetCraftsmen’s customers use for managing IP addresses. The spreadsheet is invariably out of date. A big reason is that only one person can edit the spreadsheet at a time (we’ve yet to see anyone using Google Docs for their IP Address management spreadsheets). This makes it difficult for a team to keep the spreadsheet up to date. Changes invariably happen that are never recorded.

Zeus didn’t mention DHCP, which can significantly reduce the need to manually track each device. A good DHCP product allows you to define a scope, which allows many devices to be automatically assigned IP addresses. The good products will also have an option to automatically register the device in DNS using the dynamic DNS mechanism.

It is also possible to create static DHCP entries, which assign a specific IP address to a device with the matching MAC address. This mechanism is useful for assigning IP addresses to things like printers. The benefit is that the printer’s configuration remains static, even if it moves and is assigned a new IP address. Now you have three products in one: a DNS/DHCP/IPAM (IP Address Management) product.

The network infrastructure devices, such as routers and switches and firewalls, can also be added to the IP address management system, either manually or with an automatic network discovery mechanism. The automatic mechanism guarantees that you have a complete and accurate view of the entire network address space. This is great for knowing when you are running out of address space in a given subnet.

If the DNS/DHCP/IPAM product can determine the switch port to which each device, and is loaded with location information for each switch port, you can also track the physical location of devices. It is up to you to determine how accurate the location information needs to be. It could be somewhat general, like “3rd floor, west”, or it could be more specific: “2nd floor, east, office 211B.” The challenge with location tracking is gathering the location information in the first place and the more general location information is much easier to gather and load into the system.

Finally, adding a good graphical interface to the product allows network administrators to easily see what addresses are used, which ones are vacant, and even look at the history of usage. It is nice to know when a subnet is getting close to full allocation and being able to address it before it causes a trouble ticket to be opened.

With the right systems in place, IP Address Management becomes much easier and dealing with spreadsheets. And because the address space is monitored and updated as it changes, you know that it is accurate. That’s what makes the DNS/DHCP/IPAM tools valuable.



Re-posted with Permission 

NetCraftsmen would like to acknowledge Infoblox for their permission to re-post this article which originally appeared in the Applied Infrastructure blog under http://www.infoblox.com/en/communities/blogs.html


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Nick Kelly

Cybersecurity Engineer, Cisco

Nick has over 20 years of experience in Security Operations and Security Sales. He is an avid student of cybersecurity and regularly engages with the Infosec community at events like BSides, RVASec, Derbycon and more. The son of an FBI forensics director, Nick holds a B.S. in Criminal Justice and is one of Cisco’s Fire Jumper Elite members. When he’s not working, he writes cyberpunk and punches aliens on his Playstation.


Virgilio “BONG” dela Cruz Jr.

CCDP, CCNA V, CCNP, Cisco IPS Express Security for AM/EE
Field Solutions Architect, Tech Data

Virgilio “Bong” has sixteen years of professional experience in IT industry from academe, technical and customer support, pre-sales, post sales, project management, training and enablement. He has worked in Cisco Technical Assistance Center (TAC) as a member of the WAN and LAN Switching team. Bong now works for Tech Data as the Field Solutions Architect with a focus on Cisco Security and holds a few Cisco certifications including Fire Jumper Elite.


John Cavanaugh

CCIE #1066, CCDE #20070002, CCAr
Chief Technology Officer, Practice Lead Security Services, NetCraftsmen

John is our CTO and the practice lead for a talented team of consultants focused on designing and delivering scalable and secure infrastructure solutions to customers across multiple industry verticals and technologies. Previously he has held several positions including Executive Director/Chief Architect for Global Network Services at JPMorgan Chase. In that capacity, he led a team managing network architecture and services.  Prior to his role at JPMorgan Chase, John was a Distinguished Engineer at Cisco working across a number of verticals including Higher Education, Finance, Retail, Government, and Health Care.

He is an expert in working with groups to identify business needs, and align technology strategies to enable business strategies, building in agility and scalability to allow for future changes. John is experienced in the architecture and design of highly available, secure, network infrastructure and data centers, and has worked on projects worldwide. He has worked in both the business and regulatory environments for the design and deployment of complex IT infrastructures.