/etc/resolv.conf 中的正确域设置？

Question 1

表格手册：

   nameserver Name server IP address
          Internet address of a name server that the resolver should
          query, either an IPv4 address (in dot notation), or an
          IPv6 address in colon (and possibly dot) notation as per
          RFC 2373.  Up to MAXNS (currently 3, see <resolv.h>) name
          servers may be listed, one per keyword.  If there are
          multiple servers, the resolver library queries them in the
          order listed.  If no nameserver entries are present, the
          default is to use the name server on the local machine.
          (The algorithm used is to try a name server, and if the
          query times out, try the next, until out of name servers,
          then repeat trying all the name servers until a maximum
          number of retries are made.)

   search Search list for host-name lookup.
          By default, the search list contains one entry, the local
          domain name.  It is determined from the local hostname
          returned by gethostname(2); the local domain name is taken
          to be everything after the first '.'.  Finally, if the
          hostname does not contain a '.', the root domain is
          assumed as 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.

          If there are multiple search directives, only the search
          list from the last instance is used.

          In glibc 2.25 and earlier, the search list is limited to
          six domains with a total of 256 characters.  Since glibc
          2.26, the search list is unlimited.

          The domain directive is an obsolete name for the search
          directive that handles one search list entry only.

服务器也是如此nameserver，并按顺序用于解析器查询（如果提供）。搜索选项可用于多个子域，但有一些限制。

Answer

表格手册：

   nameserver Name server IP address
          Internet address of a name server that the resolver should
          query, either an IPv4 address (in dot notation), or an
          IPv6 address in colon (and possibly dot) notation as per
          RFC 2373.  Up to MAXNS (currently 3, see <resolv.h>) name
          servers may be listed, one per keyword.  If there are
          multiple servers, the resolver library queries them in the
          order listed.  If no nameserver entries are present, the
          default is to use the name server on the local machine.
          (The algorithm used is to try a name server, and if the
          query times out, try the next, until out of name servers,
          then repeat trying all the name servers until a maximum
          number of retries are made.)

   search Search list for host-name lookup.
          By default, the search list contains one entry, the local
          domain name.  It is determined from the local hostname
          returned by gethostname(2); the local domain name is taken
          to be everything after the first '.'.  Finally, if the
          hostname does not contain a '.', the root domain is
          assumed as 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.

          If there are multiple search directives, only the search
          list from the last instance is used.

          In glibc 2.25 and earlier, the search list is limited to
          six domains with a total of 256 characters.  Since glibc
          2.26, the search list is unlimited.

          The domain directive is an obsolete name for the search
          directive that handles one search list entry only.

服务器也是如此nameserver，并按顺序用于解析器查询（如果提供）。搜索选项可用于多个子域，但有一些限制。

Question 2

nameserver仅允许一个参数。

正确的是：

nameserver 192.168.1.1
nameserver 192.168.1.2

这样您就可以解析完整限定域名。但仅凭这一点还不足以解析没有 FQDN 的简单主机名。

例如，如果您想要运行ping infra并期望它解决，infra.example.com您需要将其添加为搜索域。

search example.com

这将允许您解析infra为infra.example.com。

Answer