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Name Resolution

Name resolution is translating hostnames to IP address.

There are two ways for translation:

  • Static using /etc/hosts. It is checked before reaching the DNS server (can be modified in /etc/nsswitch.conf)
  • Dynamic using DNS servers.

The tools we can use to check name resolution:

dig $hostname
host $hostname
# older
nslookup $hostname

Other host-related files are:

/etc/hosts.deny
/etc/hosts.allow

# rarely used
/etc/host.conf

DNS​

The server DNS is configured in /etc/resolv.conf. It specifies:

  • Specify particular domains to search
  • Define a strict order of nameservers to query
  • May be manually configured/updated from a service (such as DHCP)