We know that IP Address Management is more and more important because networks became much more flexible, dynamic and people are used to bringing their own devices into corporate networks. If you've seen your What we are working on after 3.1, you won't be surprised that the new IPAM 4.0 beta contains support for BIND DNS, active detection of IP Address conflicts and better integration with User Device Tracker.
Active IP Address conflict detection
IP Address conflict is a typical nightmare of admins. IP Address conflict occurs if there are two or more devices in your network and have the same IP Address configured.
This is an issue that could arise on devices across any operating system that connects to a local area network (LAN) across any operating system, wired or wireless.
What problems may IP Address conflict cause?
Primarily network connectivity issues. Impacted machines are loosing internet access or general network connectivity until the conflict is resolved. It can impact laptop, VoIP phone or application server.
What causes IP Address conflicts?
There are three typical scenarios:
Bring Your Own Device phenomenon
Typically happens when you bring your laptop or tablet from home to the work and you still have the "home" IP address assigned which can cause collisions within corporate network. It's also typical for business trips when you got assigned static IP in the hotel and then you come back to work. It may also occur in Virtualized environments like spin up VM clone in the same subnet when virtual machine has a statically assigned IP.
DHCP servers & their configuration
Two DHCP servers are managing the same IP subnet/segment with overlapping IP addresses and DHCP server doesn't check the network IP status (IP used or not). IP address conflict happens when one machine already has a DHCP address assigned from the first DHCP server and another device is given the same IP address from secondary DHCP server. This could be a typical problem in "load balancing" DHCP configurations.
Human mistakes during IP address assignments
When admins do not use any IP address management tools it is so easy to assign already used IP address to the new device on the network.
How to manually solve IP address problem?
First, you need to know who caused the conflict and find the MAC addresses that are in conflict. If you have such possibility, unplug device which should have correct IP address. Then use 3rd machine within the subnet to PING the IP address in conflict. Use "ping -a x.x.x.x in order to get two important values. First DNS name of machine which causing the conflict, second TTL value, which may help you to identify operating system. For example Windows has typical TTL 128, Linux may have TTL 64. You may find the whole list here.
It may happen that there is no device name provided or ICMP protocol is blocked by firewall. In this case, you may use "arp -a" command and list MAC address assignment for your IP address:
MAC address is useful information, because you may identify the vendor of that device. MAC address are unique and each vendor has the first three octets of MAC are reserved for identification. You may find the MAC vendor pre-fixes list here.
With MAC address information, you may do go to the switch and block related port, or block that MAC on your wireless router/AP and let origin device to use its IP address.
How to solve IP address conflict with IPAM 4.0 Beta?
As I stated above, IPAM 4.0 can now actively detect IP address conflict. We primarily focused on alerting and information about MAC addresses which is a key-point information for conflict troubleshooting. IPAM actively scans the network and if it detects duplicate static IP assignment or duplicate IP provisioning form DHCP server, it will trigger an alert with conflict information:
Once you see IP Address in conflict, simply click on the IP or MAC address info in the alert message and it will take you to the IP address detail page, where you may see MAC address assignment history. Another IPAM 4.0 improvement is better integration with UDT product. So you may directly see device & port where are machines connected.
You may use IPAM Message Center too and get all history of IP Address conflicts:
As you see, you no longer need to use multiple commands via CLI or use 3rd machine to ping who is IP address in collision. More than that, you can see connectivity details including port and user information on one screen. Now you can use for example NPM which can remotely shut-down interface and disconnect the device from the network, or simply connect to the switch and block that port via CLI. Also, because IPAM uses alerting engine you should get IP address information before impacted person creates IT ticket (which will take some time while disconnected from network)
BIND DNS Monitoring & Management
BIND DNS is one of the most used DNS solutions. IPAM 4.0 now adds support for monitoring and management of BIND DNS services on Linux. You can now manage your Microsoft DNS and BIND DNS via one web-console. IPAM supports all important DNS tasks like automatic monitoring and management of DNS zones, two-way synchronization of DNS records and DNS server availability.
If you want to add your BIND DNS server into IPAM use short wizard that will lead you through the process of addition. When added in IPAM, it will sync and import actual BIND DNS configuration and then you can monitor or manage zones & DNS records:
IPAM 4.0 Beta is ready to be tested. All users under active IPAM maintenance may get Beta build and try it for free on non-production environment. If you would like to try it, simply fill this IPAM Beta Agreement.
As always, we also have Thwack IPAM Beta forum and it would be great to get your feedback there.
I joined SolarWinds PM team in September 2011 and I am currently part of product management team located in Czech Republic .
Before that, I spent five years developing networking products and mobile applications.
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