Transcript Introduction to Python - Kansas State University

Domain Name System (DNS)
Topic 2, Chapter 4
Network Programming
Kansas State University at Salina
DNS
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Host name to IP address look up and
reverse
Hierarchical, distributed, cached
database
Many services provided by OS
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sock.connect( (hostname, port) )
socket.getaddrinfo( hostname, None )
Advanced DNS – DNSPython
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Lookup of MX records for sending e-mail is
one example where you might need to
program a DNS lookup.
Need to add additional package for stand
alone DNS lookups.
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Book discusses PyDNS, available from source
forge.
The package index on python.org suggests that
DNSPython is a more popular DNS package.
DNSPython
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http://www.dnspython.org/
Also available from K-State Online
Get the MX targets and preferences for a
domain:
import dns.resolver
answers = dns.resolver.query(‘gmail.com', 'MX')
for rdata in answers:
print 'Host', rdata.exchange, 'has preference', rdata.preference