IP space management has become increasingly complex -- stemming from the building of new and secure network environments and a surge in the use of IP-enabled devices. Sniffing out problems early and remedying them before damage is done is the core of effective network management. IP space management is an integral part of network management and demands the same level of monitoring, quick troubleshooting, and remediation mechanisms.
IP alerting and relevant real-time information helps you avoid:
- Assigning an IP that’s already in use
- Failure to replicate IP address status changes to DHCP and DNS servers
- Erroneous DHCP configuration changes and IP conflicts caused by DHCP scope overlaps
- Unwarranted downtime due to troubleshooting of network issues and IP Conflicts
- Over or under provisioning IP addresses, DHCP scope, and split scope address depletion
- Errors during DNS record creation
Let’s take a look at some of the top IP alerts/data that give admins a heads-up, so they can avoid unexpected network downtime.
IP Conflict! Find and fix it before connectivity issues arise
The ‘IP conflict’ is a well-known problem in every network and there are many reasons that can cause one. The outcome is usually network issues and loss of user productivity. DHCP server errors, duplicate DHCP servers, BYOD, bad IP documentation, human errors, inadequate network segmentation, etc., are various reasons for IP conflicts in a network. Manually troubleshooting IP conflicts can be a very time consuming process. In turn, users experience significant downtime. Some obstacles that attribute to this include: identifying issues caused by IP conflicts, locating problematic systems, and finally taking the conflicting system off the network.
DHCP Subnets are reaching high utilization -- time to provision for more IP addresses!
When DHCP address pools are exhausted, new devices will not be able to connect to the network. In many cases, the administrator is often unaware of full DHCP scopes—that there are no IP addresses left for assignment. In some cases the admin over provisions, leaving IP addresses unused, hindering the optimal usage of IP address space. Further, if IP documentation is not updated, unused static or reserved DHCP addresses will exist. For example, IPs may have valid leases, but are no longer active. All this again means non-availability of IP addresses leading to interruption in network connectivity and user productivity.
What IP addresses are in use/available?
One of the main IP management challenges admins face is finding IP addresses that are available for use. A frequently used method is to ping for an IP, find one that doesn’t respond, and assume that it is available and then use it. But then this has its own downsides. Some examples are –
- users pinging for an available IP wouldn’t know if the IP address is a static or a dynamic one
- the IPs used for test purposes are left as such and even though technically not in use will still be unavailable
- any conflict with an IP assigned to a critical server can cause serious downtime
Even in cases where IP documentation is manually and separately maintained, most of the time this data is incomplete or obsolete.
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The creation of DNS records is a standard task for administrators. Forward DNS mapping points a domain name to an IP address. Conversely, reverse DNS maps an IP address to a domain name. The two are distinct and separate lookups, however just because a forward lookup of a domain resolves to an IP address, it doesn’t mean that a reverse lookup of the same IP address will resolve to the same domain.
Reverse DNS is also commonly used for establishing outbound e-mail server connections. It helps trace the origin of an e-mail and adds credibility to the e-mail server itself. In turn, incoming mail servers will not accept messages from an IP address that does not identify with a PTR record in a reverse DNS zone, making it very important to ensure these records are error free.
To make matters worse, the advent of IPv6 and increase the number of heterogeneous devices has further contributed to the complexity of IP space management. Administrators have come to the realization that using manual methods and spreadsheets is simply not sufficient. What mechanism do you have in place for timely warnings of your IP address data?