Что означает опция dns-search в / etc / network / interfaces?

Может кто-нибудь объяснить мне о dns-searchдирективе в /etc/network/interfacesфайле:

iface eth0 inet static
    address 192.168.3.3
    netmask 255.255.255.0
    gateway 192.168.3.1
    dns-search example.com
    dns-nameservers 192.168.3.45 192.168.8.10

Это обязательно? И как я могу это настроить?

dns-search определяет, какой домен добавляется для поиска DNS.

Обычно вы указываете тот же домен, что и возвращаемый hostname -f.

Для подробной информации смотрите следующую цитату из man resolv.conf:

   search Search list for host-name lookup.
          The  search  list  is  normally  determined from the local domain name; by default, it contains only the local domain
          name.  This may be changed by listing the desired domain search path following the search keyword with spaces or tabs
          separating  the  names.  Resolver queries having fewer than ndots dots (default is 1) in them will be attempted using
          each component of the search path in turn until a match is found.  For environments with multiple  subdomains  please
          read options ndots:n below to avoid man-in-the-middle attacks and unnecessary traffic for the root-dns-servers.  Note
          that this process may be slow and will generate a lot of network traffic if the servers for the  listed  domains  are
          not local, and that queries will time out if no server is available for one of the domains.

          The search list is currently limited to six domains with a total of 256 characters.