Specify a DNS server to be used: dnsServer is a host name or an
IP-address of the host name DNS server, which may optionally be
followed by port number, like "host:8053" when the port number
is not standard port(53).
With "dnsServer//socksV5Host", a DNS server
beyond a firewall can be referred through the specified Socks V5 server.
The Socks server is specified by its IP address with an optional port
number like "192.168.1.1:2080".
By default, name servers listed in "resolv.conf" are
added to the list of DNS servers to be used. A special dnsServ
name ".END" disables to adding such name servers. For example,
RES_NS="192.168.1.1,END." means using 192.168.1.1 only regardless of