[Plugin: ThreeWP Activity Monitor] What is "static.reverse.ltdomains.com"

and why would they constantly be trying to login to my blog?

the form is always

“IP=reverse of trailing IP ###.###.233.72 static.reverse.ltdomains.com 72.233.###.###”

and the user agent is WordPress/3.4-alpha-20205

The most maddening thing is the almost total absence of any online information on this. OTOH, ltdomains.com has been widely recognized as a spam host. OTOH, James “Macmanx” at WordPress.com suggests in a post there that the events involving static.reverse.ltdomains.com may be internal WordPress pingbacks.

One of the best things about this plugin is its ability to reveal unauthorized people trying to break in so they can be blocked if desired. Can anybody add any insight to this recurring static.reverse.ltdomains.com event for me so that I and others can evaluate it?

Thanks.

https://www.ads-software.com/extend/plugins/threewp-activity-monitor/