Apr 07, 2017 · DNS primarily uses the User Datagram Protocol (UDP) on port number 53 to serve requests.[3] DNS queries consist of a single UDP request from the client followed by a single UDP reply from the server. The Transmission Control Protocol (TCP) is used when the response data size exceeds 512 bytes, or for tasks such as zone transfers.
DNS Configuration and Data Files In addition to the in.nameddaemon, DNS on a name server consists of a configuration file called named.conf, a resolver file named resolv.conf, and four types of zone data files. Names of DNS Data Files So long as you are internally consistent, you can name the zone data files anything you want. Jun 01, 2020 · A DNS server can store and manage multiple zone files, and they can be a mixture of primary and secondary zones. In out analogy John could have a copy of TeamB list in case Fred goes on holiday. Therefore a DNS server can be both a primary and secondary name server. As DNS is an important service being able to troubleshoot it is a useful skill. By default Linux will first check it’s local host file /etc/hosts before querying DNS servers defined in /etc/resolv.conf. It is important to confirm that the correct DNS servers have been specified within this file and that you can connect to them on TCP/UDP port 53. First we will look at the file /etc/resolv.conf. This is the main configuration file library name resolver DNS. The resolver is a library in the language C, it provides access to DNS for programs in the system. Its functions are configured to the following: Each DNS zone file contains records that consist of a number of entries. As a Linux user or administrator, these records will guide Internet users to your website. The entries are also known as resource records and can vary ever so slightly in format. The following sections examine the most common record types. Edit the file /etc/netsvc.conf so that the “host =” will be pointing to local and dns as in the following hosts=local,bind For Solaris and Linux, Enable the name resolving using DNS as follows: Edit the file /etc/nsswitch.conf so that the “host:” will be pointing to local and dns as in the following hosts: files dns B)VALIDATION
For a server to be available through any NIC, edit the DNS zone file and add entries for each IP address. For example: ipaserver IN A 192.168.1.100 ipaserver IN A 192.168.1.101 ipaserver IN A 192.168.1.102
Regardless of the distribution of Linux that you are using (such as Ubuntu, CentOS, Debian, Arch, Redhat, etc), the process of determining what DNS servers are currently being used for domain name resolution is the same. To determine what DNS servers are being used, you simply need to view the contents of the “/etc/resolv.conf” file. Apr 03, 2019 · Cross-platform support is important for importing and exporting zone files, because the most common name server software, BIND, typically runs on Linux. Obtain your existing DNS zone file. Before you import a DNS zone file into Azure DNS, you need to obtain a copy of the zone file.
7.2. Domain Name Server (DNS) Configuration and Administration. At my place of employment, we are using Linux as a DNS server. It performs exceptionally well. This section will address configuration of DNS tables for these services using the BIND 8.x package which comes standard with the Red Hat distribution.
Change DNS settings on Linux. Open the resolv.conf file with an editor, such as nano , to make the necessary changes. If the file doesn’t already exist, this command creates Add lines for the name servers that you want to use. The following table displays which name server IP addresses to use Jan 12, 2015 · Sample outputs: Fig.01: Finding out your DNS lookup IP address on a Linux and Unix. How do I change or update my DNS nameservers IP address? Use a text editor such as vi, ee, emacs, joe and co to edit the file /etc/resolv.conf as root user: $ sudo vi /etc/resolv.conf. DNS lookup on a Linux and Unix systems. Now, you know your DNS name server IP address.