strange dns problem?

strange "host" header sent to my server

[Xuefer]

i've recently add a "ServerAlias *" in apache to catch all visits, and log them
some client is visiting my server using domainname that don't point to my server
for example:

GET /abc.gif HTTP/1.1
Host: www.example.com
Referer: [otherhost1.com...]

and even:

GET /abc.gif HTTP/1.1
Host: www.otherhost2.com
Referer: [myhost.com...]
in which, [myhost.com...] contains a link [otherhost2.com...]

this is the User-Agent:
Mozilla/4.0 (compatible; MSIE 5.5; Windows 98; Win 9x 4.90)

[marcs]

Is this a new site, or more importantly a new IP?

Maybe otherhost2.com had your IP address before it became yours. If some nameserver has not yet updated that info, people resolving from it would end up on your site.

[Xuefer]

hrm..
i've taken my ip so long time
and i can resolve those domainname correctly
and there're many other domain, not only 1

[Xuefer]

even more wired thing:

GET / HTTP/1.1
Host: bbs .example.com>