1 .. _example_reverse_lookup:
3 ==============================
5 ==============================
7 Reverse DNS lookup involves determining the hostname associated with a given IP address.
8 This example shows how reverse lookup can be done using unbound module.
10 For the reverse DNS records, the special domain in-addr.arpa is reserved.
11 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.
18 ctx = unbound.ub_ctx()
19 ctx.resolvconf("/etc/resolv.conf")
21 status, result = ctx.resolve(unbound.reverse("74.125.43.147") + ".in-addr.arpa.", unbound.RR_TYPE_PTR, unbound.RR_CLASS_IN)
22 if status == 0 and result.havedata:
23 print "Result.data:", result.data.domain_list
25 print "Resolve error:", unbound.ub_strerror(status)
27 In order to simplify the python code, unbound module contains function which reverses the hostname components.
28 This function is defined as follows::
31 return '.'.join([a for a in domain.split(".")][::-1])