Hostname: Unknown

What is it?

[moTi]

Every month my apache server stats show one entry on the top of "total sites" table i can't understand:

Hits: 93203 3.47%
Files: 0 0.00%
KBytes: 95661 1.24%
Visits: 12 0.03%
Hostname: Unknown

12 visits this month consuming nearly 100K kbytes and causing nearly 3.5 percent of all hits but without downloading any files? How can this be?
What is this unknown hostname visitor? A Bot? Hotlinking? Can anyone explain?
And how can i ban it from my server? Is its hostname "Unknown" or is it "" and is only translated as "Unknown" in my stats? Thanks.

[cgrantski]

When "unknown" is legitimate (rather than malevolent) it's usually a reserved IP address, i.e. the reassignable addresses in the 10, 192, 172 etc range that are assigned within a company to its internal network. For example 10.124.136.73 could be my computer's address on my network, but down the road it could be somebody else's computers's address within their network. Do a search on "reserved IP ranges" for the exact ranges, and check your raw logs to see if you have a lot of them.

So, in this case, "Unknown" means "this IP address was not listed as a public DNS". It can easily be legitimate traffic from within your network or possibly from within your hosting service's network, including uptime monitoring programs. I don't know exactly how Apache or your analytics program works, so what I'm saying here is an assumption.

You definitely don't want to block these, but most people filter them out of their analytics if they are mostly interested in public traffic.

It's also possible for malevolent entities to be hitting your site from inside your network using those reserved addresses, in which case you have a network security problem.

[moTi]

thanks for the explanation cgrantski.