在Ruby中反向DNS？

Question

我的环境中有很多没有正确清点的计算机.基本上,没有人知道哪个IP与哪个mac地址和哪个主机名相关.所以我写了以下内容:

# This script goes down the entire IP range and attempts to
# retrieve the Hostname and mac address and outputs them
# into a file. Yay!

require "socket"

TwoOctets = "10.26"

def computer_exists?(computerip)
 system("ping -c 1 -W 1 #{computerip}")
end

def append_to_file(line)
 file   = File.open("output.txt", "a")
 file.puts(line)
 file.close
end


def getInfo(current_ip)
 begin
   if computer_exists?(current_ip)
     arp_output = `arp -v #{current_ip}`
     mac_addr = arp_output.to_s.match(/..:..:..:..:..:../)
     host_name = Socket.gethostbyname(current_ip)
     append_to_file("#{host_name[0]} - #{current_ip} - #{mac_addr}\n")
   end
 rescue SocketError => mySocketError
   append_to_file("unknown - #{current_ip} - #{mac_addr}")
 end
end


(6..8).each do |i|
 case i
   when 6
     for j in (1..190)
       current_ip = "#{TwoOctets}.#{i}.#{j}"
       getInfo(current_ip)
     end
   when 7
     for j in (1..255)
       current_ip = "#{TwoOctets}.#{i}.#{j}"
       getInfo(current_ip)
     end
   when 8
     for j in (1..52)
       current_ip = "#{TwoOctets}.#{i}.#{j}"
       getInfo(current_ip)
     end
 end
end

一切正常,除了它没有找到反向DNS.

我得到的示例输出是这样的:

10.26.6.12 - 10.26.6.12 - 00:11:11:9B:13:9F
10.26.6.17 - 10.26.6.17 - 08:00:69:9A:97:C3
10.26.6.18 - 10.26.6.18 - 08:00:69:93:2C:E2

如果我这样做,nslookup 10.26.6.12那么我得到正确的反向DNS,以便显示我的机器正在看到DNS服务器.

我试过了Socket.gethostbyname,gethostbyaddr但它不起作用.

任何指导将不胜感激.

Answer 1

今天我还需要反向DNS查找,我发现了非常简单的标准解决方案:

require 'resolv'
host_name = Resolv.getname(ip_address_here)

它似乎使用超时,这有助于粗略的情况.

Answer 2

我会退房getaddrinfo.如果你更换线:

host_name = Socket.gethostbyname(current_ip)

有:

host_name = Socket.getaddrinfo(current_ip, 0, Socket::AF_UNSPEC, Socket::SOCK_STREAM, nil, Socket::AI_CANONNAME)[0][1]

该getaddrinfo函数返回一个数组数组.您可以在以下位置了解更多信息:

Ruby Socket文档