Astrit,
This depends on what urged the avast! team to block.
I am a volunteer website code analyst here at these forums.
avast! team members like for instance Milos & F. Chytry decide what IP (IP-range) should be blocked/unblocked...
If there are thousands of domains assigned to one single IP a single IP block could mean frustration ahead for many.
Therefore this should be tested before implementation. If there are three bad domains (according to malware reported)
blocking several thousand domains should not be a first option.
There are 33 websites on that IP:
http://myip.ms/info/whois/64.202.120.73None blocked here:
http://www.ipvoid.com/scan/64.202.120.73/On the other hand the hosting party also has a responsibility towards those that are hosted to keep their services cleansed, take malware down as soon as reported or found, do not leave issues with a LONG OVERDUE status as they are, secure and harden their servers and log and IDS log.
It is a pity there are still hosting parties that care less about security but see their services more as an income model first...
Then also webmasters have a task securing their websites through upgrading and updating their website software and other measures (scanning, PHP security etc. etc.)
polonus