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require 'ipaddr'
require 'socket'
require 'timeout'
#
# This class is responsible for doing forward/reverse DNS lookups
#
class DNSUtil
#
# Return the reverse DNS for the specified IP address, nil on failure.
#
def DNSUtil.ip_to_hostname( ip )
resolved = nil
begin
timeout( 4 ) do
begin
Socket.getaddrinfo(ip, 'echo').each do |a|
resolved = a[2] if ( a )
end
rescue SocketError
resolved = nil
end
end
rescue Timeout::Error => e
resolved = nil
end
resolved
end
#
# Convert a hostname to an IP address, return nil on failure.
#
def DNSUtil.hostname_to_ip( hostname )
resolved = nil
begin
timeout( 4 ) do
begin
Socket.getaddrinfo(hostname, 'echo').each do |a|
resolved = a[3] if ( a )
end
rescue SocketError
resolved = nil
end
end
rescue Timeout::Error => e
resolved = nil
end
resolved
end
end
if __FILE__ == $0 then
%w( ssh.steve.org.uk ipv6.steve.org.uk ).each do |name|
puts "Hostname test: #{name} #{DNSUtil.hostname_to_ip(name) }"
end
%w( 80.68.85.46 80.68.85.48 2001:41c8:125:46::22 ).each do |name|
puts "Hostname test: #{name} #{DNSUtil.ip_to_hostname(name) }"
end
end
|
