python网络编程学习笔记(四)：域名系统

def nslookup(qstring,qtype,verbose=1):
print qstring
nslist=findnameservers(qstring)
print nslist
if nslist==None:
raise RuntimeError,'找不到服务器'
if verbose:
print "服务器:",",".join(nslist)
return getrecordsfromnameserver(qstring,qtype, nslist)

def getreverse(query):
"""Given the query, returns an appropriate reverse lookup string
under IN-ADDR.ARPA if query is an IP address; otherwise, returns None.
This function is not IPv6-compatible."""
if re.search('^/d+/./d+/./d+/./d+$', query):
octets = query.split('.')
octets.reverse()
return '.'.join(octets) + '.IN-ADDR.ARPA'
return None

def formatline(index, typename, descr, data):
retval = "%-2s %-5s" % (index, typename)
if isinstance(data,list):
return retval
else:

data = data.replace("/n", "/n ")
if descr != None and len(descr):
retval += " %-12s" % (descr + ":")
return retval + " " + data

DNS.DiscoverNameServers()
query1=raw_input('输入网站：')
queries = [(query1, DNS.Type.ANY)]
donequeries = []
descriptions = {'A': 'IP address',
'TXT': 'Data',
'PTR': 'Host name',
'CNAME': 'Alias for',
'NS': 'Name server'}

while len(queries):
(query, qtype) = queries.pop(0)
if query in donequeries:
# Don't look up the same thing twice
continue
donequeries.append(query)
print "-" * 77
print "Results for %s (lookup type %s)" %(query, DNS.Type.typestr(qtype))
print
rev = getreverse(query)
if rev:
print "IP address given; doing reverse lookup using", rev
query = rev

answers = nslookup(query, qtype, verbose = 0)
if not len(answers):
print "Not found."

count = 0
for answer in answers:
count += 1
if answer['typename'] == 'MX':
print formatline(count, answer['typename'],
'Mail server',
"%s, priority %d" % (answer['data'][1],
answer['data'][0]))
queries.append((answer['data'][1], DNS.Type.A))
elif answer['typename'] == 'SOA':
data = "/n" + "/n".join([str(x) for x in answer['data']])
##print data
print formatline(count, 'SOA', 'Start of authority', data)
elif answer['typename'] in descriptions:
##print answer['data']
print formatline(count, answer['typename'],
descriptions[answer['typename']], answer['data'])
else:
print formatline(count, answer['typename'], None,
str(answer['data']))
if answer['typename'] in ['CNAME', 'PTR']:
queries.append((answer['data'], DNS.Type.ANY))
if answer['typename'] == 'NS':
queries.append((answer['data'], DNS.Type.A))

本人在运行时，总是报错，没找到原因，望高手指点。