4812f02dd0
bypassing the cache response stage and uniquifying mesh states. Four EDNS option lists were added to module_qstate (module_qstate.edns_opts_*) to store EDNS options from/to front/back side. - Added two flags to module_qstate (no_cache_lookup, no_cache_store) that control the modules' cache interactions. - Added code for registering inplace callback functions. The registered functions can be called just before replying with local data or Chaos, replying from cache, replying with SERVFAIL, replying with a resolved query, sending a query to a nameserver. The functions can inspect the available data and maybe change response/query related data (i.e. append EDNS options). - Updated Python module for the above. - Updated Python documentation. git-svn-id: https://unbound.nlnetlabs.nl/svn/trunk@3947 be551aaa-1e26-0410-a405-d3ace91eadb9
38 lines
1.2 KiB
ReStructuredText
38 lines
1.2 KiB
ReStructuredText
.. _example_reverse_lookup:
|
|
|
|
Reverse DNS lookup
|
|
==================
|
|
|
|
Reverse DNS lookup involves determining the hostname associated with a given IP
|
|
address.
|
|
This example shows how reverse lookup can be done using unbound module.
|
|
|
|
For the reverse DNS records, the special domain in-addr.arpa is reserved.
|
|
For example, a host name for the IP address ``74.125.43.147`` can be obtained
|
|
by issuing a DNS query for the PTR record for address
|
|
``147.43.125.74.in-addr.arpa.``
|
|
|
|
Source code
|
|
-----------
|
|
|
|
::
|
|
|
|
#!/usr/bin/python
|
|
import unbound
|
|
|
|
ctx = unbound.ub_ctx()
|
|
ctx.resolvconf("/etc/resolv.conf")
|
|
|
|
status, result = ctx.resolve(unbound.reverse("74.125.43.147") + ".in-addr.arpa.", unbound.RR_TYPE_PTR, unbound.RR_CLASS_IN)
|
|
if status == 0 and result.havedata:
|
|
print "Result.data:", result.data.domain_list
|
|
elif status != 0:
|
|
print "Resolve error:", unbound.ub_strerror(status)
|
|
|
|
In order to simplify the python code, unbound module contains the
|
|
:meth:`unbound.reverse` function which reverses the hostname components.
|
|
This function is defined as follows::
|
|
|
|
def reverse(domain):
|
|
return '.'.join([a for a in domain.split(".")][::-1])
|