I am trying something new. My sites are constantly being scraped and attacked. Usually this is from web hosts, not from home and business user IP addresses.

So I am thinking "Why not block those IP address ranges at the firewall?" I am trying to think of what I lose by not letting these scripts crawl my web sites.

The first thing I broke was email. It's important not to block that. I am now only blocking these IP's on port 80. I might change that in the future and only allow them on port 25.

What else might I break? What do you think?

Here's the list of wen host IP's I'm blocking today:
Code:
# Amazon EC2
50.16.0.0/14
67.202.0.0/18
75.101.128.0/17
79.125.0.0/17
174.129.0.0/16
184.72.0.0/15
204.236.128.0/17
# Bulletproof Web (Chinese Hosting)
91.201.64.0/22
# Staminus Communications (http://staminus.net/)
72.20.0.0/18
# Limestone Networks (http://www.limestonenetworks.com/)
74.63.192.0/18
# Dedibox (http://www.dedibox.fr/)
88.191.3.0/24
88.191.4.0/22
88.191.8.0/21
88.191.16.0/20
88.191.32.0/18
88.191.64.0/17
88.191.128.0/18
88.191.192.0/19
88.191.224.0/20
88.191.240.0/21
88.191.248.0/24
# Rackspace
69.20.0.0/17
173.203.0.0/16
174.143.0.0/16
184.106.0.0/16
# Nobis Technology Group, LLC (http://www.nobistech.net)
64.120.0.0/17
69.147.224.0/19
108.62.0.0/16
173.208.0.0/17
173.234.0.0/16
174.34.128.0/18
# CentralHost
98.158.16.0/20
# Softlayer
67.228.0.0/16
174.36.0.0/23
# Q9 Networks (q9.com)
67.210.208.0/20
# Krypt Technologies (http://www.vpls.net)
98.126.0.0/16
# Steadfast Networks (steadfast.net)
208.100.0.0/18
# FortressITX
208.116.0.0/18
# Fortress Colocation Centers (fortresscolo.com)
173.225.16.0/20 
# GigeNET (http://www.gigenet.com)
209.212.144.0/20
# dimenoc.com
66.7.192.0/19
# ThePlanet
67.18.0.0/15
70.84.0.0/14
74.52.0.0/14
174.120.0.0/14
174.132.0.0/15
# GoDaddy
72.167.0.0/16
97.74.0.0/16
# GoDaddy Singapore
182.50.128.0/19
# Singlehop
184.154.0.0/16
# HostNOC
64.120.128.0/17
184.82.0.0/16
# Atomic Data Centers LLC (Tier 2 host at XOXO)
64.244.48.0/20
71.5.104.0/21
# Infolink (http://www.infolink.com)
64.251.0.0/19
# fdcservers.net
76.73.0.0/17
204.45.0.0/16
# calpop.com
208.70.72.0/21
# CWIE (http://www.cwie.com)
64.38.192.0/17
# KeyWeb AG
84.19.160.0/19
87.118.64.0/18
# galaxyvisions.com
209.104.192.0/19
# Peer1 Dedicated Hosting
216.157.0.0/18
216.157.64.0/19
216.157.96.0/20
# Evolution Online Ltd. (http://www.evolution.co.il/)
195.190.23.0/24
# Netelligent (http://netelligent.ca/)
209.44.96.0/19
# Hurricane Electric
65.49.0.0/15
# dcsmanage.com
66.79.160.0/19
205.209.128.0/18
# BlueHost
67.20.64.0/18
74.220.192.0/19
# LiquidWeb
67.225.128.0/17
67.227.128.0/17
69.167.128.0/18
# Turnkey Internet (http://www.turnkeyinternet.net/)
67.231.240.0/20
# InterServer (http://www.interserver.net)
69.10.32.0/19
# LunarPages.com
74.50.0.0/19
# Iomart Hosting
78.129.128.0/17
109.169.64.0/19
# OVH Hosting
87.98.128.0/18
91.121.64.0/18
94.23.0.0/18
188.165.192.0/18
# oc3networks.com
96.44.128.0/18
# InMotion Hosting
74.124.210.0/23
# Net2EZ (http://www.net2ez.com)
64.93.64.0/19
# steadfast.net
69.162.128.0/18
# MediaTemple (http://mediatemple.net/)
205.186.128.0/18
# xsserver.eu
109.230.208.0/20
109.230.240.0/20
# 1&1 Internet AG (http://oneandone.net)
87.106.0.0/16
# Eltel (http://www.eltel.net)
81.222.192.0/18
# giga-hosting.biz
79.143.176.0/20
# register.it
81.88.48.0/20
# Servage Hosting (http://www.servage.net)
77.232.68.0/23
92.61.144.0/20
# hosteurope.de
178.77.64.0/18
# noc4hosts.com
66.232.96.0/19
96.31.64.0/19
# iweb.com
67.205.64.0/18
184.107.0.0/16
# netdirekt
89.149.192.0/18
188.72.192.0/18
217.20.112.0/20
# VolumeDrive
173.242.112.0/20
# dotnetdotcom.org
208.115.111.240/28
# leaseweb.com
85.17.0.0/16
# Melbourne Network Solutions (http://melbourne.co.uk)
87.237.56.0/21
# nthost.ru
217.147.29.0/24
64.13.192.108
# SoftLayer
50.22.0.0/15
67.228.0.0/16
173.192.0.0/15
208.43.0.0/16
# Savvis
64.41.128.0/17
66.119.32.0/19
165.193.0.0/16
# jumpline.com
64.6.224.0/19
# Cyberverse
66.172.0.0/18
# Layered Technologies (layertech.com)
72.232.0.0/16
72.233.0.0/17
# Colo4Dallas
72.249.0.0/17
72.249.128.0/18
# westhost.com
209.236.64.0/20
# Bergdorf Group (http://bergdorf-group.com/)
91.224.160.0/23
# Hetzner Online AG (http://www.hetzner.de/)
46.4.0.0/16
88.198.0.0/16
188.40.0.0/16
213.133.96.0/19
# fasthosts.co.uk
213.171.192.0/19
# ukrtelecom.ua Utel DataCenter, Ukraine
213.186.112.0/20
# altushost.com
213.5.64.0/21
# completeweb.net
216.226.128.0/19
# Hot Networking
65.120.238.0/24
# Global Network Access (gnax.net)
64.22.64.0/18
72.9.224.0/19
# Psychz Networks
173.224.208.0/20
199.71.212.0/22
216.24.192.0/20
# Dreamhost
173.236.128.0/17
# sagonet.com
207.150.160.0/19
# Trustica Housed Servers (http://www.trustica.cz)
81.0.246.0/26
# Mojohost
99.192.128.0/17
# BITEC Hosting
178.33.2.156/30
# SERVER.UA Ukraine Dedicated Service (http://www.server.ua)
195.189.226.0/23
# Daily Internet Services VPS (http://www.daily.co.uk/)
195.234.10.0/23
# Flexiant (http://www.flexiant.com/)
109.231.64.0/18
# eNET XLHost (http://www.xlhost.com/)
209.190.0.0/16
# Slicehost
209.20.64.0/19
# Fantastic VPS (http://fantastic-vps.com/)
212.124.116.0/24