Empty user-agent

but it's lying

[dstiles]

I've had three instances of an Empty UA recently, through three different broadband suppliers' IPs. Why the UA is hiding the Mozilla version and not the actual browser UA is a mystery. Possibly something broken in Trident? The rest of the headers seem to be the usual random assortment of semi-valid or valid data. Each UA below is complete and exact.

Empty (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; GTB6; Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) ; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; OfficeLiveConnector.1.3; OfficeLivePatch.0.0; msn OptimizedIE8;ENUS)

Empty (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; GTB6; Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) ; .NET CLR 1.0.3705; Media Center PC 4.0; .NET CLR 2.0.50727; .NET CLR 1.1.4322; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)

Empty (compatible; MSIE 8.0; Windows NT 6.0; WOW64; Trident/4.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; eSobiSubscriber 2.0.4.16; .NET CLR 3.5.30729; .NET CLR 3.0.30729)

[incrediBILL]

I just noticed Empty today as well in my BOUNCED LOG, gave me a chuckle.