7.4 DNS Resolver Configuration

DNS resolver settings are configured using the resolver compound statement:

resolver {
  config filename;
  max-cname-chain num;
}

resolver: config filename

Name of the resolver configuration file to use, instead of the default /etc/resolv.conf.

resolver: max-cname-chain num

Maximum allowed length of a DNS CNAME chain that will be followed. A CNAME chain is a sequence of CNAME records pointing to another CNAMEs. Although CNAME chains are not considered a good practice, many sites still use them. By default the mailfromd resolver allows at most one CNAME record pointing to a CNAME (this corresponds to max-cname-chain 2). If you need to follow longer chains, raise this value. Note however, that using values greater than 5 is not a good idea, anyway.