Domain Name Service (DNS)

Domain Name Service (DNS) hosts are queried by domain names and IP addresses. DNS is a client-server system in which the domain name interpreter accesses the Domain Name Server to link the domain name with the IP address or other suitable hosts. Gnu c Library resolver (3) can also find IP addresses in files or through Network Information Service (NIS. Some programs (such as GNOME) want the host name to be resolved to an IP address and have a valid domain name. This is really not suitable, because the host name and domain name are two completely different things. To support these software, we need to ensure that the system host name can be resolved. The common practice is to add a line of content with IP address and system Host Name in/etc/hosts. If your system has a permanent IP address, use this address; otherwise, use 127.0.0.1. 127.0.0.1 localhost127.0.1.1 uranus uses hostname -- fqdn to check whether your system's host name can be resolved to an IP address and has a valid domain name.