The order in which your system selects a method of resolving hostnames to IP addresses is controlled
by the Name Service Switch (NSS) configuration file /etc/nsswitch.conf. As mentioned in the
previous section, typically static hostnames defined in the systems /etc/hosts file have precedence
over names resolved from DNS. The following is an example of the line responsible for this order of
hostname lookups in the file /etc/nsswitch.conf.
hosts:
files mdns4_minimal [NOTFOUND=return] dns mdns4
• files first tries to resolve static hostnames located in /etc/hosts.
• mdns4_minimal attempts to resolve the name using Multicast DNS.
• [NOTFOUND=return] means that any response of notfound by the preceeding mdns4_minimal
process should be treated as authoritative and that the system should not try to continue hunting for
an answer.
• dns represents a legacy unicast DNS query.
• mdns4 represents a Multicast DNS query.
To modify the order of the above mentioned name resolution methods, you can simply change the
hosts: string to the value of your choosing. For example, if you prefer to use legacy Unicast DNS
versus Multicast DNS, you can change the string in /etc/nsswitch.conf as shown below.
hosts:
files dns [NOTFOUND=return] mdns4_minimal mdns4
by the Name Service Switch (NSS) configuration file /etc/nsswitch.conf. As mentioned in the
previous section, typically static hostnames defined in the systems /etc/hosts file have precedence
over names resolved from DNS. The following is an example of the line responsible for this order of
hostname lookups in the file /etc/nsswitch.conf.
hosts:
files mdns4_minimal [NOTFOUND=return] dns mdns4
• files first tries to resolve static hostnames located in /etc/hosts.
• mdns4_minimal attempts to resolve the name using Multicast DNS.
• [NOTFOUND=return] means that any response of notfound by the preceeding mdns4_minimal
process should be treated as authoritative and that the system should not try to continue hunting for
an answer.
• dns represents a legacy unicast DNS query.
• mdns4 represents a Multicast DNS query.
To modify the order of the above mentioned name resolution methods, you can simply change the
hosts: string to the value of your choosing. For example, if you prefer to use legacy Unicast DNS
versus Multicast DNS, you can change the string in /etc/nsswitch.conf as shown below.
hosts:
files dns [NOTFOUND=return] mdns4_minimal mdns4
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