Postfix, Rate Limiting Inbound Emails Using SenderScore And Memcache

I received email from someone fiew days ago, he directed me to an article about senderscore and and asked if I could make it usable. Actually, I’m not very familiar with how senderscore work. I’ve read the article and see the FAQ at https://senderscore.org/. I have found that senderscore can be queried with a format like this:

reversed.ip.address.score.senderscore.com

Ie, I want to know the score value of ip address 202.127.97.97, the format of the query would be like this:

$ dig a 97.97.127.202.score.senderscore.com +short
127.0.4.75

Look at the answers given by senderscore’s NS. last octet is the score of the ip address 202.127.97.97, which scored 75.

Excerpts from senderscore faq:

All scores are based on a scale of 0 to 100, where 0 is the worst, and 100 is the best possible score. A score represents that IP address’s rank as measured against other IP addresses, much like a percentile ranking.

Now back to the article, The authors make a perl module that can perform queries to senderscore ns, put a “reputation score” into memcache, at the same time, calculating how many times an ip address connected to our smtp.

Let’s begin, first of all download Policy::Memcache from this git repository 
Create a working directory, and extract the tarball.

$ mkdir pol-mem && cd pol-mem
$ tar --extract --file=petermblair-libemail-f73612c.tar.gz petermblair-libemail-f73612c/perl/senderscore/memcache/
$ mv petermblair-libemail-f73612c/perl/senderscore/memcache/* .