utility: ifconfig

While adding some consequent IP's aliases on one interface,  and then
deleting the first of them,  all others deleting with one. 
It revealed while those aliases are not from subnet of real address for
this intereface.
Example :

eth0: 192.168.0.1/24
adding 10 aliases: 192.168.1.1-10
deleting: 192:168.1.1

result in deleteing all 192.168.1.1-10 aliases.

Thanks for paying attention.
Andy