Module: MXRecord

Defined in:
lib/mx_record.rb

Class Method Summary collapse

Class Method Details

.mail_servers(domain) ⇒ Object

Obtain the mail exchange record for a particular domain.

Returns an array of Resolv::DNS::Resource::IN::MX records e.g. for Google:

[ #<Resolv::DNS::Resource::IN::MX:0x007faaac870da8 @preference=50, @exchange=#<Resolv::DNS::Name: alt4.aspmx.l.google.com.>, @ttl=347>,

#<Resolv::DNS::Resource::IN::MX:0x007faaac8769b0 @preference=20, @exchange=#<Resolv::DNS::Name: alt1.aspmx.l.google.com.>, @ttl=347>,
#<Resolv::DNS::Resource::IN::MX:0x007faaac874db8 @preference=40, @exchange=#<Resolv::DNS::Name: alt3.aspmx.l.google.com.>, @ttl=347>,
#<Resolv::DNS::Resource::IN::MX:0x007faaac87abf0 @preference=30, @exchange=#<Resolv::DNS::Name: alt2.aspmx.l.google.com.>, @ttl=347>,
#<Resolv::DNS::Resource::IN::MX:0x007faaac87f830 @preference=10, @exchange=#<Resolv::DNS::Name: aspmx.l.google.com.>, @ttl=347> ]



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# File 'lib/mx_record.rb', line 14

def self.mail_servers(domain)
  Resolv::DNS.open do |dns|
    dns.getresources(domain, Resolv::DNS::Resource::IN::MX)
  end
end

.primary_server(domain) ⇒ Object

Obtain the preferred mail server based on the MX record’s preference.

Returns a String containing the mail server name e.g. aspmx.l.google.com; returns nil if no servers are found.



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# File 'lib/mx_record.rb', line 24

def self.primary_server(domain)
  servers = mail_servers(domain)

  return nil if servers.empty?

  primary_server = servers.first

  servers.each do |server|
    primary_server = server if server.preference < primary_server.preference
  end

  primary_server.exchange.to_s
end