On Wed, 14 Nov 2012 20:49:19 -0500, Roy Smith wrote: >> I'm slightly surprised that there's no way with the Python stdlib to >> point a DNS query at a specific server > > Me too, including the "only slightly" part. The normal high-level C > resolver routines (getaddrinfo/getnameinfo, or even the old > gethostbyname series), don't expose any way to do that.
That's because the high-level routines aren't tied to DNS. gethostbyname() and getaddrinfo() use the NSS (name-service switch) mechanism, which is configured via /etc/nsswitch.conf. Depending upon configuration, hostnames can be looked up via a plain text file (/etc/hosts), Berkeley DB files, DNS, NIS, NIS+, LDAP, WINS, etc. DNS is just one particular back-end, which may or may not be used on any given system. If you specifically want to perform DNS queries, you have to use a DNS-specific interface (e.g. the res_* functions described in the resolver(3) manpage), or raw sockets, rather than a high-level interface such as gethostbyname() or getaddrinfo(). -- http://mail.python.org/mailman/listinfo/python-list
