odd web log entry

[Lloyd Kvam]

222.185.109.136 - - [02/Aug/2007:05:46:07 -0400] "GET http://207.150.184.73/proxygrade.php?hash=E54B5A88967F08F244A2DA1B00506714C03DEC23EC07 HTTP/1.1" 404 291 "-" "Mozilla/4.0 (compatible; MSIE 6.01; Windows NT 5.0)"

136.109.185.222.in-addr.arpa domain name pointer 136.109.185.222.broad.cz.js.dynamic.163data.com.cn.
73.184.150.207.in-addr.arpa domain name pointer unknown.sagonet.net.

OrgName:    Sago Networks 
OrgID:      SAGO
Address:    4465 W. Gandy Blvd.
Address:    Suite 800
City:       Tampa
StateProv:  FL
PostalCode: 33611
Country:    US


I assume this was an attempt to use my web server as a client proxy to
reach a different site.  There's only one request from that IP address.

This is the first time I've noticed this kind of request coming through.
Please let me know if any of you folks think there are grounds for
concern or if you think I should be taking any followup action.

-- 
Lloyd Kvam
Venix Corp