import dns.resolver def get_mx_domains(hostname) -> [str]: answers = dns.resolver.query(hostname, "MX") ret = [] for a in answers: record = a.to_text() # for ex '20 alt2.aspmx.l.google.com.' r = record.split(" ")[1] # alt2.aspmx.l.google.com. ret.append(r) return ret _include_spf = "include:" def get_spf_domain(hostname) -> [str]: """return all domains listed in *include:*""" try: answers = dns.resolver.query(hostname, "TXT") except dns.resolver.NoAnswer: return [] ret = [] for a in answers: # type: dns.rdtypes.ANY.TXT.TXT for record in a.strings: record = record.decode() # record is bytes if record.startswith("v=spf1"): parts = record.split(" ") for part in parts: if part.startswith(_include_spf): ret.append(part[part.find(_include_spf) + len(_include_spf) :]) return ret