I have a linux box with two windows virtuals machines. There is no problem on the Windows, but on linux the www.xysblogs.org always points to www.xys.org.

I checked the name resolving, the resolving is correct. The www.xysblogs.org is using a diffent IP address.

$ nslookup www.xysblogs.org
Server: 10.2.32.5
Address: 10.2.32.5#53

Non-authoritative answer:
Name: www.xysblogs.org
Address: 70.40.210.121

$ nslookup www.xys.org
Server: 10.2.32.5
Address: 10.2.32.5#53

Non-authoritative answer:
Name: www.xys.org
Address: 69.93.206.250