Sorry code source of the previous post, it seems outlook.com refuse it :'( So, this is an extract of the access.log when we try to access IBM.com: 1380789449.550 262 10.0.0.62 TCP_MISS/302 725 GET http://www.ibm.com/ - HIER_DIRECT/129.42.60.216 text/html 1380789449.683 124 10.0.0.62 TCP_MISS/301 651 GET http://www.ibm.com/us/en - HIER_DIRECT/129.42.60.216 text/html 1380789450.029 343 10.0.0.62 TCP_MISS/200 4368 GET http://www.ibm.com/us/en/ - HIER_DIRECT/129.42.60.216 text/html 1380789450.335 90 10.0.0.62 TCP_MISS/200 595 GET http://pt200204.unica.com/ntpagetag.gif? - HIER_DIRECT/173.223.178.24 image/gif 1380789450.473 225 10.0.0.62 TCP_MISS/200 6690 GET http://consent.truste.com/notice? - HIER_DIRECT/46.51.168.42 text/javascript 1380789450.637 24 10.0.0.62 TCP_MISS/200 5588 GET http://consent.truste.com/notice? - HIER_DIRECT/46.51.168.42 text/javascript 1380789450.724 47 10.0.0.62 TCP_MISS/200 1911 POST http://gtssl-ocsp.geotrust.com/ - HIER_DIRECT/199.7.71.72 application/ocsp-response 1380789450.793 57 10.0.0.62 TCP_MISS/200 1421 GET http://service.maxymiser.net/cg/v5us/? - HIER_DIRECT/23.56.241.207 text/javascript 1380789450.803 126 10.0.0.62 TCP_MISS/200 1495 GET http://www.ibm.com/common/twitter/ibm.xml? - HIER_DIRECT/129.42.60.216 text/xml 1380789450.834 90 10.0.0.62 TCP_MISS/200 595 GET http://pt200204.unica.com/ntpagetag.gif? - HIER_DIRECT/173.223.178.24 image/gif 1380789450.834 90 10.0.0.62 TCP_MISS/200 595 GET http://pt200204.unica.com/ntpagetag.gif? - HIER_DIRECT/173.223.178.24 image/gif 1380789451.199 23 10.0.0.62 TCP_MISS/200 429 GET http://consent.truste.com/noticemsg? - HIER_DIRECT/46.51.168.42 image/gif 1380789451.484 308 10.0.0.62 TCP_MISS/304 235 GET http://consent-pref.truste.com/? - HIER_DIRECT/54.217.210.13 - 1380789451.524 28 10.0.0.62 TCP_MISS/200 445 GET http://consent-pref.truste.com/eupreferencemanager/css? - HIER_DIRECT/54.217.210.13 text/css 1380789451.897 48 10.0.0.62 TCP_MISS/500 374 POST http://consent-pref.truste.com/eupreferencemanager/truste - HIER_DIRECT/54.217.210.13 text/plain 1380789451.965 115 10.0.0.62 TCP_MISS/500 374 POST http://consent-pref.truste.com/eupreferencemanager/truste - HIER_DIRECT/54.217.210.13 text/plain The behaviour of the blank popup exist on any browser, One possibility to avoid it is to disable Java script in the browser. Blocking the access to Truste.com is not a valid solution. Unfortunately, I don't see anything which could help in the log :'(.