< script src="http://1.2.3.4/bmi-int-js/bmi.js" language="javascript">< /script>

The "connecting to 1.2.3.4" is an HTML code-snippet that AT&T is injecting in to HTML pages that calls a javascript image accelerator (presumably hitting some AT&T cache) sitting on the server with the IP address "1.2.3.4". They're doing this to improve image quality/download speed on mobiles, but given this is a firefox forum I'm willing to bet the "34 people" that have this problem as well are using their AT&T 3G connection for internet tethering. To confirm this, navigate to one of these slow pages in firefox and use the menus to find: View ==> Page Source You should see right at the top something like: < script src="http://1.2.3.4/bmi-int-js/bmi.js" language="javascript">< /script> Given you're on a laptop, you probably don't want this image shrinking service so you need to block access the site "1.2.3.4". I'm sure you use to be able to block access to certain sites in the admin tool widget on FF5 but I couldn't find it anywhere. I installed a FF add-on called "blocksite" and told it to block "1.2.3.4". I noticed a significant improvement. I actually had this problem on the UK telco O2 as well so it isn't just AT&T that is doing it.