farrokhi/dnsdiag
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Fix looking up NS record from root server

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- also resolve hostname to IP if name is given as dns server
- raise timeout to 2 seconds
This commit is contained in:
Babak Farrokhi 2016-06-15 17:14:10 +04:30
parent 364312cbac
commit b23a3ce081
Signed by: farrokhi
GPG Key ID: 6B267AD85D632E9A
1 changed files with 16 additions and 6 deletions
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22
dnstraceroute.py
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@ -38,7 +38,6 @@ import time
import dns.query import dns.query
import dns.rdatatype import dns.rdatatype
import dns.resolver import dns.resolver
from cymruwhois import cymruwhois from cymruwhois import cymruwhois
__author__ = 'Babak Farrokhi (babak@farrokhi.net)' __author__ = 'Babak Farrokhi (babak@farrokhi.net)'
@ -181,7 +180,7 @@ def ping(resolver, hostname, dnsrecord, ttl):
_ttl = ttl _ttl = ttl
try: try:
resolver.query(hostname, dnsrecord) resolver.query(hostname, dnsrecord, raise_on_no_answer=False)
except dns.resolver.NoNameservers as e: except dns.resolver.NoNameservers as e:
if not quiet: if not quiet:
@ -199,8 +198,8 @@ def ping(resolver, hostname, dnsrecord, ttl):
pass pass
except SystemExit: except SystemExit:
pass pass
except: except Exception as e:
print("unxpected error: ", sys.exc_info()[0]) print("unxpected error: ", e)
sys.exit(1) sys.exit(1)
else: else:
reached = True reached = True
@ -222,7 +221,7 @@ def main():
dnsrecord = 'A' dnsrecord = 'A'
count = 30 count = 30
timeout = 1 timeout = 2
dnsserver = dns.resolver.get_default_resolver().nameservers[0] dnsserver = dns.resolver.get_default_resolver().nameservers[0]
dest_port = 53 dest_port = 53
hops = 0 hops = 0
@ -273,6 +272,16 @@ def main():
color = Colors(color_mode) color = Colors(color_mode)
# check if we have a valid dns server address
try:
ipaddress.ip_address(dnsserver)
except ValueError: # so it is not a valid IPv4 or IPv6 address, so try to resolve host name
try:
dnsserver = socket.getaddrinfo(dnsserver, port=None, family=socket.AF_INET)[1][4][0]
except OSError:
print('Error: cannot resolve hostname:', dnsserver)
sys.exit(1)
resolver = dns.resolver.Resolver() resolver = dns.resolver.Resolver()
resolver.nameservers = [dnsserver] resolver.nameservers = [dnsserver]
resolver.timeout = timeout resolver.timeout = timeout
@ -286,7 +295,8 @@ def main():
trace_path = [] trace_path = []
if not quiet: if not quiet:
print("%s DNS: %s:%d, hostname: %s, rdatatype: %s" % (__PROGNAME__, dnsserver, dest_port, hostname, dnsrecord)) print("%s DNS: %s:%d, hostname: %s, rdatatype: %s" % (__PROGNAME__, dnsserver, dest_port, hostname, dnsrecord),
flush=True)
while True: while True:
if shutdown: if shutdown: