Re: localhost pitfall in resolver/solving "Host or domain name not found. Name service error for name=localhost type=A: Host not found" (also type=AAAA)

[Wietse Venema]

Does this help?

        Wietse

smtp_dns_resolver_options (default: empty)
       DNS Resolver options for the Postfix SMTP client.  Specify zero or more
       of the following options, separated by  comma  or  whitespace.   Option
       names  are  case-sensitive. Some options refer to domain names that are
       specified in the file /etc/resolv.conf or equivalent.

       res_defnames
              Append the current domain name to single-component names  (those
              that do not contain a "." character). This can produce incorrect
              results, and is the hard-coded behavior prior to Postfix 2.8.

       res_dnsrch
              Search for host names  in  the  current  domain  and  in  parent
              domains. This can produce incorrect results and is therefore not
              recommended.

       This feature is available in Postfix 2.8 and later.