DNS Name, IP Address Resolver, and Whois Tool

The domain name system (DNS) is a naming database that makes it possible to locate internet domain names and translate them into IP addresses. If someone types www.solarwinds.com into a web browser, for instance, a server can use DNS behind the scenes to map the same name to the corresponding IP address, which would be something similar in structure to 121.12.12.121. Web browsers rely on DNS to quickly provide the information needed to connect users to the right host.

Thanks to DNS, a user only needs to remember the domain name of a site instead of the entire IP address. When a user types in the name of any website, the DNS name resolution process starts. To get the IP address, the server must use a domain name resolver to send queries to the name servers. The first answer the browser will get is the root server, and then it’ll get the top-level domain (TLD). The servers of the TLD the user wants to visit (like .com, .net, and .org) will refer their queries to the next step in searching for authoritative servers that know the complete IP. At this point, the domain name is resolved.

DNS name resolution can be recursive or iterative. With recursive DNS name resolution, the client relies on the local server to either give the requested mapping or an error message. An application generates a DNS query and sends it to the domain name resolver so it can find the destination IP address. Afterward, the query is forwarded to the local DNS server. If the server knows the IP address, it’ll send a response to the domain resolver, and if not, it sends the query to the root name server.

With iterative DNS name resolution, each server that doesn’t know the mapping sends the IP address of the next server to the one that requested it. This allows the client to return the best answer it can. Iterative DNS name resolution follows the same protocols as recursive DNS name resolution until the query is sent to the root name server. From there, the root name server returns the IP address of the TLD to the local server. The local server then contacts the TLD server and either returns the destination host’s IP or its local DNS server. If it returns the server’s address, the user can find the IP address of the destination host by contacting the destination’s local DNS server. Finally, the mapping is passed from the host’s local DNS server to the domain resolver and back to the host. At this point, the domain name is resolved.

A DNS name resolver is a local server designed to act as a central database of DNS nameservers and manage DNS requests for clients on your network. For every domain address on the internet, there’s at least one IP address. IP addresses can change at any time, but the domain name never changes. The DNS system serves as an up-to-date index of those IP addresses, and a DNS name resolver is the outward-facing part of the system receiving the DNS requests.

You can think of the DNS name resolver as the first stop on the road toward DNS name resolution. When a client contacts the domain name resolver, the resolver contacts multiple different authoritative nameservers—the servers actually containing IP address information—to find the necessary IP address and fulfill the request. With the help of DNS resolvers, your computer doesn’t have to store thousands of addresses for multiple nameservers.

DNS name resolvers can help increase the efficiency of any DNS system. Without these tools, every computer on your network would need to be provided with the individual addresses of several authoritative nameservers to perform DNS name resolution and would require you to constantly keep the server list for each computer updated. Using a DNS name resolver means all clients on a network have access to a centralized list of authoritative nameservers, which can dramatically reduce the management time needed to keep systems current.

DNS name resolvers can also help maximize performance. Enterprise-grade domain name resolvers are designed to keep a cache of the results they send to clients. If another client requests the same IP address later, the resolver can simply recall the IP address and provide it directly without having to contact any external nameservers. This helps improve DNS response time on a local level and reduces the network load.

Whois is an internet record designed to identify who owns a domain and provide information on how to get in contact with them. Each Whois record contains the contact information for the person, group, or company associated with a domain name and includes the following:

• The name and contact information of the registrant, the person who owns the domain
• The name and contact information of the registrar, the organization or commercial entity that registered the domain name
• Administrative and technical contact information
• The registration dates
• The nameservers
• The most recent update
• The expiration date of the domain

There are two different models for storing DNS Whois information: thin and thick. A thin Whois model only provides the registrar, nameservers, and registration dates. A thick Whois model offers contact information on top of the same details the thin model provides. It takes a lot of work to find Whois information given how many registrars and servers there are, which is why using a DNS Whois tool can go a long way.

A DNS Whois tool or DNS Whois resolver is a tool built to allow you to easily look up Whois information and report on domain names, URLs, and IP, network, and email addresses. These tools are also built to perform forward and reverse DNS lookups and keep a cache of DNS name resolution results.

SolarWinds^® Engineer’s Toolset™ (ETS) offers over 60 must-have network management and troubleshooting tools. With this essential tool set, you get access to IP address monitoring tools like the Subnet Calculator, DHCP Scope Monitor, DNS Structure Analyzer, DNS Audit tool, IP Address Management tool, and Spam Blacklist tool. You can monitor IP addresses, resolve domain names, get DHCP scopes, perform DNS structure analysis, and more.