Dr_lipshits -
The site that hosts your domain has probably been hacked into by some 10 year old snot nosed punk, and he is using it as a bounce point to attack other systems. Welcome to the internet
We have over 50 systems online under our control, and each one of them gets probed between 10 to 500 times a day from all over the world. You just need to make sure that your host has a good security plan to protect you from these evil little bastards. A couple of hints, if your hosts run's bsd or linux, and run's with open shells, then you should be very afraid of your server being compromised at any given time. What I mean by a open shell access, is if you are able to telnet or ssh into the box without first having to have given the admin your ip # from the box you use, then the access is open, anyone can try brute force attacks on you. In fact if your using a cable modem, then all 10 year olds in your neighborhood probably already have your username and password for ftp and telnet, the only way to stay secure is to use ssh and secure ftp which transmit's your username and password already encrypted, and have the box only allow ip #'s to login that have been ok'ed by the system admin. Good Luck
Tim