$ dig www.twitter.com +short
twitter.com.
199.59.149.230
199.59.148.10
199.59.150.7
199.59.150.39

$ simpledns -h
usage: simpledns [-h] [-b BIND_ADDR] [-p BIND_PORT]
                 [--upstream-ip UPSTREAM_IP] [--upstream-port UPSTREAM_PORT]
                 [--query-timeout QUERY_TIMEOUT] [--min-ttl MIN_TTL]
                 [--max-ttl MAX_TTL] [--cache-size CACHE_SIZE] [-t]
                 [--hosts-file HOSTS_FILE] [--dispatch-conf DISPATCH_CONF]
                 [-v {0,1,2}] [-q] [-V]

A lightweight yet useful proxy DNS server

optional arguments:
  -h, --help            show this help message and exit
  -b BIND_ADDR, --bind-addr BIND_ADDR
                        local address to listen
  -p BIND_PORT, --bind-port BIND_PORT
                        local port to listen
  --upstream-ip UPSTREAM_IP
                        upstream DNS server ip address
  --upstream-port UPSTREAM_PORT
                        upstream DNS server port
  --query-timeout QUERY_TIMEOUT
                        time before close port used for querying
  --min-ttl MIN_TTL     the minimum time a record is held in cache
  --max-ttl MAX_TTL     the maximum time a record is held in cache
  --cache-size CACHE_SIZE
                        record cache size
  -t, --tcp-server      enables TCP serving
  --hosts-file HOSTS_FILE
                        hosts file
  --dispatch-conf DISPATCH_CONF
                        URL dispatch conf file
  -v {0,1,2}, --verbosity {0,1,2}
                        output verbosity
  -q, --quiet           disable output
  -V, --version         print version number and exit

address=/example1.com/1.1.1.1
server=/example2.com/1.1.1.2