logwatch - sendmail unknow users
I've been getting a lot of these unknown local users entry under sendmail section in my logwatch reportUnknown local users:
alex@somedomain.com
from friend@friend.net [xxx.xxx.xxx.xxx] 2 time(s).
alice@somedomain.com
from friend@friend.net [xxx.xxx.xxx.xxx] 2 time(s).
bill@somedomain.com
from friend@friend.net [xxx.xxx.xxx.xxx] 2 time(s).
brenda@somedomain.com
from friend@friend.net[xxx.xxx.xxx.xxx] 2 time(s).
brian@somedomain.com
from friend@friend.net [xxx.xxx.xxx.xxx] 1 time(s).
Where
friend@friend.net IP:xxx.xxx.xxx.xxx is my friend's ip address and isp hostname. I am hosting his domain (somedomain.com) on my vps. Does this mean his home pc is infected by some spam bots?