Cannot access a specific remote IP address on Mac Os X 10.7.5
The problem lies on the LogMeIn Hamachi network which, on IPv4, tries to get all the 5.0.0.0/8 netblock even if there are classes opf public IP addresses in there.
Solved by setting LogMeIn to use IPv6 only.

See:

http://community.logmein.com/t5/Hamachi/Hamachi-and-the-5-0-0-0-8-netblock/td-p/55826

and 

http://community.logmein.com/t5/Hamachi/5-x-x-x-Address-Range/td-p/83996