Bulk IP address DNS lookup

Lookup hostnames for IP addresses loaded from file.

Program uses goroutines to speed up the process.

Written in Go (Golang).

Usage

Requires Go installed.

Build and run:

go build
./main

Example input addresses.txt:

172.217.20.206
216.58.215.110
127.58.215.110
99.83.207.202
212.77.98.9

Example output:

172.217.20.206
        waw02s08-in-f206.1e100.net
        waw02s08-in-f14.1e100.net

216.58.215.110
        waw02s17-in-f14.1e100.net

212.77.98.9
        www.wp.pl

99.83.207.202
        aafc88a28d9997374.awsglobalaccelerator.com

127.58.215.110
        err

Command line arguments ./main -help:

Usage:
  -e string
        Hostnames value on error (default "err")
  -f string
        Format output (ip, hostnames) (default "%v\n\t%v\n")
  -i string
        Input file name (default "./addresses.txt")
  -s string
        Hostnames separator (default "\n\t")
  -t bool
        Trim hostnames "." suffix (default true)

Note that -t argument requires -t= notation e.g. -t=false as it is bool type.