5.2. Programming Assignment 2 - DNS MX Record Lookups¶
A list of e-mail servers
You are to add a few lines of code to the stub program provided. (Download,
dns_MX_stub.py) The function MX_lookup()
should return a list of strings for e-mail servers. The servers should be sorted
by the domain’s priorities as specified in their DNS MX records.
Here is a sample output from the provided stub program:
Enter a domain name to look up: sal.ksu.edu (100, <DNS name mx2.cc.ksu.edu.>) (100, <DNS name mx3.cc.ksu.edu.>) (10, <DNS name postman.sal.ksu.edu.>) (100, <DNS name mx1.cc.ksu.edu.>)
Here is what the output of the completed project should look like:
Enter a domain to look up: sal.ksu.edu postman.sal.ksu.edu. mx1.cc.ksu.edu. mx2.cc.ksu.edu. mx3.cc.ksu.edu.
Notice that in the initial program, the
servers list contains tuples
where the first value of the tuple is a MX preference and the second value
is the server name. Thus, all that is needed is to sort the list and print
the second value of each tuple.
This is obviously a pretty short assignment, intended mostly to let you work some with lists, tuples and strings.
dnspython is needed for the programming assignment. It
can be installed with the easy_install command from the
setuptools package. See Installation of Python Packages for a description of how to