Addresses that does not resolve to a hostname is now handled.

1 files changed, 21 insertions, 13 deletions

diff --git a/dnscheck_nsd.py b/dnscheck_nsd.py
index c2b10ed..d911622 100644
--- a/dnscheck_nsd.py
+++ b/dnscheck_nsd.py
@@ -18,12 +18,20 @@ logger.addHandler(ch)
 VERBOSE = False
 
 
+def get_hostname(addr):
+    hostname = addr
+    try:
+        return gethostbyaddr(addr)[0]
+    except herror:
+        logger.error('No hostname could be found for %s.' % addr)
+        return hostname
+
 def get_resolver(nameserver=None, lifetime=30):
     resolver = dns.resolver.Resolver()
     resolver.lifetime = lifetime
     if nameserver:
         try:
-            resolver.nameservers=[gethostbyname(nameserver)]
+            resolver.nameservers = [gethostbyname(nameserver)]
         except gaierror:
             try:
                 resolver.nameservers = [nameserver]  # It is an IP address
@@ -44,17 +52,17 @@ def compare_soa(zone, resolvers):
                     logger.info('NS %s: %s' % (resolver.nameservers[0], answer))
                 else:
                     try:
-                        logger.info('NS %s: %s' % (gethostbyaddr(resolver.nameservers[0])[0], answer))
+                        logger.info('NS %s: %s' % (get_hostname(resolver.nameservers[0]), answer))
                     except herror:
                         logger.info('NS %s: %s' % (resolver.nameservers[0], answer))
         except dns.exception.Timeout:
-            logger.error('%s timed out. SOA request for %s failed.' % (gethostbyaddr(resolver.nameservers[0])[0], zone))
+            logger.error('%s timed out. SOA request for %s failed.' % (get_hostname(resolver.nameservers[0]), zone))
             return 'timeout'
         except dns.resolver.NoAnswer:
-            logger.error('%s returned no answer for %s.' % (gethostbyaddr(resolver.nameservers[0])[0], zone))
+            logger.error('%s returned no answer for %s.' % (get_hostname(resolver.nameservers[0]), zone))
             return None
         except dns.resolver.NXDOMAIN:
-            logger.error('NS %s responded domain not found (NXDOMAIN) for %s.' % (gethostbyaddr(resolver.nameservers[0])[0], zone))
+            logger.error('NS %s responded domain not found (NXDOMAIN) for %s.' % (get_hostname(resolver.nameservers[0]), zone))
             return None
         except dns.resolver.NoNameservers:
             logger.error('No non-broken nameservers are available to answer the query for %s.' % zone)
@@ -73,20 +81,20 @@ def print_soa(zone, resolvers):
             if resolver.nameservers[0] == '127.0.0.1' or resolver.nameservers[0] == '::1':
                 print 'NS %s: %s' % (resolver.nameservers[0], answer)
             else:
-                print 'NS %s: %s' % (gethostbyaddr(resolver.nameservers[0])[0], answer)
+                print 'NS %s: %s' % (get_hostname(resolver.nameservers[0]), answer)
         except dns.exception.Timeout:
-            print '%s timed out. SOA request for %s failed.' % (gethostbyaddr(resolver.nameservers[0])[0], zone)
+            print '%s timed out. SOA request for %s failed.' % (get_hostname(resolver.nameservers[0]), zone)
         except dns.resolver.NoAnswer:
-            logger.error('%s returned no answer for %s.' % (gethostbyaddr(resolver.nameservers[0])[0], zone))
+            logger.error('%s returned no answer for %s.' % (get_hostname(resolver.nameservers[0]), zone))
         except dns.resolver.NXDOMAIN:
-            logger.error('NS %s responded domain not found (NXDOMAIN) for %s.' % (gethostbyaddr(resolver.nameservers[0])[0], zone))
+            logger.error('NS %s responded domain not found (NXDOMAIN) for %s.' % (get_hostname(resolver.nameservers[0]), zone))
         except dns.resolver.NoNameservers:
             logger.error('No non-broken nameservers are available to answer the query for %s.' % zone)
 
 
 def check_auth(zone, resolver):
     try:
-        nameserver = gethostbyaddr(resolver.nameservers[0])[0]
+        nameserver = get_hostname(resolver.nameservers[0])
         answer = resolver.query(zone, 'NS')
         if VERBOSE:
             logger.info('Checking if NS %s authoritative for %s...' % (nameserver, zone))
@@ -97,13 +105,13 @@ def check_auth(zone, resolver):
                     logger.info('NS %s is authoritative for %s...' % (nameserver, zone))
                 return True
     except dns.exception.Timeout:
-        logger.error('%s timed out. NS request for %s failed.' % (gethostbyaddr(resolver.nameservers[0])[0], zone))
+        logger.error('%s timed out. NS request for %s failed.' % (get_hostname(resolver.nameservers[0]), zone))
         return None
     except dns.resolver.NoAnswer:
-        logger.error('%s returned no answer for %s.' % (gethostbyaddr(resolver.nameservers[0])[0], zone))
+        logger.error('%s returned no answer for %s.' % (get_hostname(resolver.nameservers[0]), zone))
         return None
     except dns.resolver.NXDOMAIN:
-        logger.error('NS %s responded domain not found (NXDOMAIN) for %s.' % (gethostbyaddr(resolver.nameservers[0])[0], zone))
+        logger.error('NS %s responded domain not found (NXDOMAIN) for %s.' % (get_hostname(resolver.nameservers[0]), zone))
         return None
     except dns.resolver.NoNameservers:
         logger.error('No non-broken nameservers are available to answer the query for %s.' % zone)