What Are Lame Delegations?

In the Domain Name System (DNS), “lame delegations” or “lame responses” occur when one or more nameservers that have been delegated to provide authoritative DNS information for a domain fail to do so. Lame delegations can result in longer DNS lookup times, poor user experiences, adverse SEO performance, potential resolution failures, vulnerability to DNS attacks, and degradation of DNS performance for the domain.

The Domain Name System is responsible for translating names such as web domains into IP addresses. To make the web easier for users to navigate, web domains consist of names like “example.com” that are easy to read and remember. However, to connect to a website, machines need to know the actual IP address, which is typically a long string of alphanumeric characters (e.g., 2600:1401:4000:5b1::b63). Like a phone directory, DNS quickly supplies the IP address for any web domain that a user types into a web browser. DNS also provides IP addresses when users click on links, or when devices or applications need access to other similar resources on the web.

When a user or device attempts to connect to a website, device, or internet-connected resource, their device seeks to discover the IP address for the selected website by sending a DNS request or query to a network of DNS servers. Authoritative DNS nameservers (NS) are responsible for keeping official DNS records that identify the correct IP address for each website, device, or resource. Recursive DNS servers are intermediaries between the user’s device and the authoritative DNS server. Recursive servers, also known as recursive resolvers, reside closer to users and keep many DNS records stored in cache memory, enabling them to quickly produce IP addresses for web domains that users frequently or repeatedly request. If the recursive server doesn’t have a DNS record stored, it will query other nameservers or eventually get the data from the authoritative name servers that have been delegated to keep NS records for the domain. The recursive server passes the IP address back to the user’s device, which loads the correct website in an application such as a browser or makes the correct connection to an application or service.

Lame delegation occurs when the nameservers responsible for providing an authoritative answer for a domain fail to respond to DNS queries or respond improperly in some way. Lame delegation may be the result of:

• Unavailability. Lame delegations may occur when a nameserver is unreachable, not functional, or the IP address for the nameserver is not routed.
• Misconfiguration. When nameservers are incorrectly configured or their DNS software is not functioning properly, they will fail to respond to queries.
• Lack of connectivity. Network connectivity issues or firewall restrictions may cause nameservers to become unreachable.
• Inconsistency. If DNS configurations across several delegated nameservers are inconsistent, it may result in lame delegation. Inconsistent configurations may result when there are differences in DNS zone data or incorrect zone transfers.
• Nonexistent. If the specified nameservers for a domain do not exist or have been decommissioned without updating the delegation records, the nameservers will not be able to respond correctly to a DNS query.
• Lack of updates. When a new delegation has been made but a particular nameserver has not yet been configured or updated, the nameserver will be unable to return an accurate response to a DNS query.

Lame delegations can have a variety of adverse impacts.

• Longer lookup times. With lame delegation, DNS requests may take longer to resolve, creating delays in loading web pages and accessing web resources.
• Resolution failures. When a delegation is lame, DNS resolution for the domain may fail, resulting in an inability for users and devices to reach the domain. This can lead to loss of functionality and downtime.
• Degraded user experiences. Longer lookup times and resolution failures inevitably mean poor experiences for users, who may experience delays, timeouts, or errors.
• Security threats. Attackers may exploit unresponsive or misconfigured nameservers to launch an array of DNS attacks such as DNS hijacking, cache poisoning, or amplification attacks.
• Poor organic search performance. Domains with frequent lame delegations may not rank as highly in search engine results pages (SERPs) since search engines will have difficulty accessing, crawling, and indexing the domain.
• Damage to online reputation. When lame delegations occur frequently, the online reputation of a website or domain may be damaged, and the trust of users and customers may diminish.

IT and security teams can follow several best practices to prevent lame delegations and ensure that DNS services continue to operate efficiently.

• Regularly verifying configuration of nameservers can ensure that nameservers are set up correctly and are properly configured to respond to DNS queries.
• Distributing DNS delegation across multiple nameservers in different locations and networks can help to increase redundancy, enabling the system to continue handling queries if one server becomes unresponsive.
• Proactively monitoring nameserver health and responsiveness will allow early detection of issues.
• Performing regular DNS audits helps verify that the delegation information is up to date, accurate, and consistent across all authoritative DNS servers.
• Enabling DNS Security Extensions (DNSSEC) improves the security and integrity of DNS resolution, ensuring that DNS responses are authentic and mitigating the risk of DNS spoofing.
• Choosing a superior DNS hosting provider will ensure access to robust infrastructure, DNS expertise, and tools to prevent lame delegations.