socket.gethostbyaddr() wrongly returning a DNS CNAME as the 'primary' hostname

[cjblaine]

Python 2.7.1 (perhaps others)

I believe this is a bug. Comments?

Docs state: Return a triple (hostname, aliaslist, ipaddrlist)
where hostname is the primary host name responding to the
given ip_address, aliaslist is a (possibly empty) list of
alternative host names for the same address, and ipaddrlist
is a list of IPv4/v6 addresses for the same interface on the
same host (most likely containing only a single address).

my-dns-cname.our.org is a CNAME record for primary.our.org
primary.our.org has IP address xx.xx.xx.xx

import socket
socket.gethostbyaddr('xx.xx.xx.xx')

returns:

('my-dns-cname.our.org', ['primary.our.org'], ['xx.xx.xx.xx'])

 

[Ned Deily]

<850c85c0-be6e-4eec-b6b1-5c79e1716f6d@glegroupsg2000goo.googlegroups.com

Python 2.7.1 (perhaps others)

I believe this is a bug. Comments?

Docs state: Return a triple (hostname, aliaslist, ipaddrlist)
where hostname is the primary host name responding to the
given ip_address, aliaslist is a (possibly empty) list of
alternative host names for the same address, and ipaddrlist
is a list of IPv4/v6 addresses for the same interface on the
same host (most likely containing only a single address).

my-dns-cname.our.org is a CNAME record for primary.our.org
primary.our.org has IP address xx.xx.xx.xx

import socket
socket.gethostbyaddr('xx.xx.xx.xx')

returns:

('my-dns-cname.our.org', ['primary.our.org'], ['xx.xx.xx.xx'])

socket.gethostbyaddr() is pretty much just a transparent wrapper around
the platform's C library function of the same name. See if a simple C
program with a similar call to gethostbyaddr produces the same results.
The code in question for Python 2.7 is here:

http://hg.python.org/cpython/file/a6b772599594/Modules/socketmodule.c