|Before we move further with the different methods of DNS lookups, let us understand what exactly we mean by "IP address". It is an numerical value representing the geographical location of a computer. Usually, the IP address is used in the network packets that travel from one computer to another. These packets include information such as the source and destination of the packet, the network header that contains the information, and finally, the data that is eventually sent back to the client. Basically, the IP address serves as a routing marker that guides the packets of information along.|
One method of DNS lookups is the so-called standard query/response format. This method allows for the storage of static or dynamic IP addresses. For example, the static IP addresses are used during the normal operation of the Domain Name System (DNS). The DNS server returns a DNS query, and when a match is found, it creates a record in the DNS database.
If the server cannot find a matching entry, it will retry until a match is found. If no matching entry is found, the DNS server does the next step and creates an opaque zone file, or cache. The cache is used by the DNS client to find and refer to a resource. The next method for IP address discovery is the IP-based service or I-record system. This method uses the IP address within the IP packet to identify and establish a session. The I-record system is essentially used for the purpose of establishing interactive sessions.
Users of Microsoft Windows operating systems can establish a DNS resolution by using one of the following methods: A) A Microsoft-issued user manual that provides instructions on how to do it. B) An Internet Information Services (IIS) manual that provides information on I-record methods and the procedure to use them to configure DNS servers. C) A licensed software that is based on the ICND and IETF protocols that provide information about DNS and IP networks. D) A third-party vendor that provides I-record based on TCP/IP and NTP.
To connect to an IP-based domain name system (DNS), you can use the syntax for the IpTLD RRsets as the name of domain name or IP address. The DNS server replies with an IP-based query, and the DNS server searches for a host specified by the IP address. If the IP address or domain name can be found, then the name of the server used to discover names of domain-records is returned. If not, the search fails and a message is sent to the user, sometimes with an error message.
On the other hand, if the domain name cannot be resolved, then it is up to the user to enter an IP-based wildcard name domain name, which works just like an IP-domain name. An IP-domain name is used to specify a point in the network where multiple IP addresses can be listed to identify a single unit. An IP Wildcard-name, on the other hand, is a domain name that contains one or more IP addresses. For IP-wildcard-names, DNS resolver service functions differently from typical DNS.
The DNS domain name system in Germany, unlike the US, allows only the last-several domain names to resolve. This means that if the domain name is already in use by another system, it will fail to resolve and a different DNS resolver service is required. As a result, users may receive an error message such as "DNS name lookup for 'urn DWBzrK' failed." On the other hand, if the IP address cannot be resolved, the DNS server returns "Domain name or IP Address not found."
To fix this problem, a DNS server can use a two technique algorithm, namely, the on-demand lookups and the parallel lookups. With the on-demand lookups, when the client sends a query with the same domain name, an instance of the DNS server which handles the IP address can yield the same information if the query is sent in a specific time. The parallel lookup algorithm is quite similar to the on-demand algorithm wherein the server has to check whether there is any information on the name. If yes, it returns immediately. The problem is that the IP address may not be in use anymore, hence the server will have to retry the query before returning any answer. To remedy this problem, an additional IP Address look-up algorithm known as session IDs was introduced to resolve this issue.