Constant hits from unknown source

[Tim]

Checking the Latest Visitors in my site sates, I notice that I have been receiving these strange hits. Approximately every 15 minutes for the past couple weeks (at least), something has been hitting my root directory. The only thing that changes each time is the Host number; always same size in bytes and agent. Anybody have a clue as to what's going on?

Host: 219.214.152.80
Url: /
Http Code : 200
Date: Sep 04 23:11:28
Http Version: HTTP/1.1"
Size in Bytes: 5905
Referer: -
Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows 98)

[Vin DSL]

Looks like a Japanese Yahoo search engine bot, to me...