Program:	pydig (a DNS query tool written in Python)
Version:	1.3.1
Written by:	Shumon Huque <shuque@gmail.com>

Description:

	A program to perform DNS queries and exercise various existing
	and emerging features of the DNS protocol. It works mostly 
	similar to the dig program that comes with ISC BIND. I wrote
	it mostly for fun, and for helping me to learn more esoteric
	features of the DNS. Occasionally I use this to quickly prototype
	proposed enhancements to the DNS. Some of the more recent
	such features include EDNS client subnet, chain query, 
	cookies, DNS over TLS, and more.

	RR type and class codes (qtype and qclass) unknown to this 
	program can be specified with the TYPE123 and CLASS123 syntax.

Usage:

	pydig [list of options] <qname> [<qtype>] [<qclass>]
	pydig @server +walk <zone>

Options:

        -h                        print program usage information
        @server                   server to query
        -pNN                      use port NN (default is port 53)
        -bIP                      use IP as source IP address
        +tcp                      send query via TCP
        +ignore                   ignore truncation (don't retry with TCP)
        +aaonly                   set authoritative answer bit
        +cdflag                   set checking disabled bit
        +norecurse                set rd bit to 0 (recursion not desired)
        +edns[=N]                 use EDNS with specified version (default 0)
        +ednsflags=N              set EDNS flags field to N
        +ednsopt=###[:value]      set generic EDNS option
        +bufsize=NN               use EDNS with specified UDP payload size
        +dnssec                   request DNSSEC RRs in response
        +nsid                     send NSID (Name Server ID) option
        +expire                   send an EDNS Expire option
        +padding                  send an EDNS Padding option
        +cookie[=xxx]             send EDNS cookie option
        +subnet=addr              send EDNS client subnet option
	+chainquery[=name]        send EDNS chain query	option
        +hex                      print hexdump of rdata field
        +walk                     walk (enumerate) a DNSSEC secured zone
	+0x20			  randomize case of query name (bit 0x20 hack)
        -4                        perform queries with IPv4
        -6                        perform queries with IPv6
        -d                        request additional debugging output
	-k/path/to/keyfile        use TSIG key in specified file
        -iNNN                     use specified message id
        -tNNN                     use this TSIG timestamp (secs since epoch)
        -y<alg>:<name>:<key>      use specified TSIG alg, name, key
        +tls=auth|noauth          use TLS with|without authentication
        +tls_port=N               use N as the TLS port (default is 853)
        +tls_fallback             Fallback from TLS to TCP on TLS failure
        +tls_hostname=name        Check hostname in TLS server certificate

Example usage:

       pydig www.example.com
       pydig www.example.com A
       pydig www.example.com A IN
       pydig @10.0.1.2 example.com MX
       pydig @dns1.example.com _blah._tcp.foo.example.com SRV
       pydig @192.168.42.6 +dnssec +norecurse blah.example.com NAPTR
       pydig @dns2.example.com -6 +hex www.example.com
       pydig @192.168.72.3 +walk secure.example.com
       pydig @192.168.14.7 -yhmac-md5:my.secret.key.:YWxidXMgZHVtYmxlZG9yZSByaWNoYXJkIGRhd2tpbnM= example.com axfr
       pydig @192.168.14.7 -yhmac-sha256:my.secret.key.:NBGFWFr+rR/uu14B94Ab1+u81M2DTqB65gOv16nG8Xw= example.com axfr
       pydig @185.49.141.38 +tls=auth +tls_hostname=getdnsapi.net www.ietf.org AAAA

Limitations:

	Certain combinations of options don't make any sense (eg.
	+tcp and +edns0). pydig doesn't bother to check that, and 
	just ignores the nonsensical ones. Certain options also 
	imply other options, eg. +walk and +dnssec imply +edns0.

	For TSIG (Transaction Signature) signed messages, the program
	supports HMAC-MD5/SHA1/SHA256/SHA384/SHA256. It doesn't yet
	support GSS-TSIG.

	It decodes but does not yet verify signatures in DNSSEC secured 
	data.

	It does not perform iterative resolution (eg. dig's +trace).

	Specific features of TLS depend on the version of Python in
	use. TLS server certificate verification and hostname 
	verification require quite recent versions of Python 2.7.x.

Pre-requisites:

	Python 2.7 (or later) or Python 3.x

Platforms:

	Tested on the following platforms:
		Solaris 8, 9, 10, and 11
		Linux 2.x
		FreeBSD 9.x and 10.x
		Mac OS X 10.4 through 10.7

	and with Python 2.7.x and Python 3.x.

Installation:

	1. (as root) python setup.py install

Shumon Huque
E-mail: shuque -at- gmail.com
Web: https://www.huque.com/

Copyright (c) 2006 - 2017, Shumon Huque. 
All rights reserved. This program is free software; you can redistribute 
it and/or modify it under the same terms of the GNU General Public License.