Question about a perl script

Aspec has asked for the wisdom of the Perl Monks concerning the following question:

I'm having issues posting to this page for some reason so I'm hoping that maybe a shorter post will help. Please check this pastebin page for the information about my question. I'm keeping my fingers crossed this post goes through.....

UPDATE:
I'm thinking that it was maybe some of my html tags I was using in the process of creating my post or maybe it was just too long as it was my very first post on this forum and I just registered 10 minutes ago. Probably a spam prevention measure I would think

Following content appended from paste bin by GrandFather

Hello Monks,
This is my first time here on your forums and I have absolutely no perl experience what-so-ever but I was hoping that someone could answer a question for me. I am working on creating a blacklist to block tor exit nodes to help thwart some of the attacks that I've been seeing take place on my website. I found a post with a perl script that will download the list of exit nodes and place them each on a new line. I'm always cautious about running a script on my machine that I have absolutely no idea what it does so I wanted someone to see if they could tell me if this is the case or not.

found is a list of all the tornodes updated every half an hour. This list SHOULD include the exit,entries and bridge nodes used to connect and browse through tor
use this perl script to gather the ips from a downloaded webpage
perl -lne 'print $& if /(\d+.){3}\d+/' downloadedwebpage.html > listof
+ips.out
[download]
it will give you a list of ips, one per line. i have tried to find something that will do this without Perl script but after many hours searching i could not find one. hope this helps

I also found this link from the page referenced above that has the list of ips exactly how I want them to come through.

Does this seem like a reasonable solution to anyone? I would have to think there should be another way to do this but if this works they way the poster states then I might just use it. Anyone care to look at that code real quick and see if it would be safe and/or offer up a suggestion on a different solution to this. I'm trying to get the exit mode list downloaded every 30 minutes and have it update my systems banlist accordingly. I can handle the second part of this but I wanted some input as to getting the data onto my machine in the first place in a format that can be used for my banlist.

Thank you in advance for your assistance,

Bob

Comment on Question about a perl script Download Code

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Re: Question about a perl script
by GrandFather (Saint) on Jul 28, 2014 at 02:22 UTC

The Perl one liner you show should be pretty safe to run. To get a handle on what's going on start with perlintro and command switches then take a look at perlrequick for an overview of the regular expression bit.

Perl is the programming world's equivalent of English

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Re: Question about a perl script
by Anonymous Monk on Jul 28, 2014 at 02:46 UTC

The one-liner looks reasonable... ish... It will match something like '19216811a99b12?0', as well as IPs. There is also that "You're connected from..." thing on the page.

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Re^2: Question about a perl script

by 1s44c (Scribe) on Jul 28, 2014 at 09:43 UTC

Your right of course. reasonable...ish isn't good enough when any single error could mess up whatever the top poster is doing with these IPs.

Cleaner output, but needs Regexp::Common:

perl -MRegexp::Common='net' -lne 'print $1 if /($RE{net}{IPv4})/' 'TOR Node List.html'

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[d/l]

Re: Question about a perl script
by 1s44c (Scribe) on Jul 28, 2014 at 09:30 UTC

That perl one-liner is fine but it is only a little part of what you want to do. You will either need to feed those IPs into iptables and drop their traffic or configure your web browser to stop those IPs accessing or maybe just posting to your forum.

Did you see http://www.reaper-x.com/2012/05/15/how-to-block-tor-on-apache-and-nginx/ ?

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Re: Question about a perl script
by Aspec (Initiate) on Jul 28, 2014 at 16:19 UTC

Thank you everyone for the input. I will look into the link in blocking tor access on apache and if anyone has a good reference for understanding perl (a beginners guide) I would love to hear some recommendations about getting a grasp on the language. Thanks again for all of the input, I really appreciate it all. If someone can show me how to take that script and have it add to iptables just so I have another solution I would be extremely grateful.

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Re^2: Question about a perl script

by AppleFritter (Vicar) on Jul 29, 2014 at 16:58 UTC

Howdy Aspec, here's some links that might be useful for getting started with Perl:

Introductions, first steps and general information:

Tutorials:

FAQs:

The perlfaq manpage
- perlfaq1 - General Questions about Perl
- perlfaq2 - Obtaining and Learning about Perl
- perlfaq3 - Programming Tools
- perlfaq4 - Data Manipulation
- perlfaq5 - Files and Formats
- perlfaq6 - Regular Expressions
- perlfaq7 - General Perl Language Issues
- perlfaq8 - System Interaction
- perlfaq9 - Web, Email and Networking
Just the FAQs (from The Perl Journal, by Dominus)

Books:

Learning Perl, aka "The Llama" (June 2011)
Beginning Perl (by Ovid; August 2012)
Intermediate Perl, aka "The Alpaca" (July 2012)
Mastering Perl (January 2014)
Programming Perl, aka "The Camel"; a must-have (February 2012)
Modern Perl (April 2014; PDF here)
Advanced Perl Programming (June 2005)
Perl Best Practices (July 2005)
Effective Perl Programming, aka "The Shiny Ball" (April 2010)
Perl Cookbook, aka "The Big-Horn Sheep" (August 2003)
Perl Hacks (May 2006)
Perls of Wisdom (December 2004)
Introducing Regular Expressions (July 2012)
Mastering Regular Expressions (August 2006)
Mastering Algorithms with Perl, aka "The Timber Wolf" (August 1999)
Higher-Order Perl (March 2005; PDF here)
Perl Testing (July 2006)
Perl Medic (March 2004)

If you have more questions, by all means feel free to ask them here on Perlmonks, too. The Monastery welcomes everyone who seeks enlightenment.

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Re^2: Question about a Perl script

by Athanasius (Archbishop) on Jul 29, 2014 at 12:23 UTC

Hello Aspec, and welcome to the Monastery!

if anyone has a good reference for understanding perl (a beginners guide) I would love to hear some recommendations about getting a grasp on the language.

The Monastery has a lot of information on this topic (Super Search is your friend!). For example, you will find many useful references in the March, 2014, thread Want to learn PERL.

For books, see davido’s homepage, especially Learning Perl (the “Llama Book”), and Modern Perl by chromatic. The latter is available for free download from http://onyxneon.com/books/modern_perl/.

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

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