Firmware 3.3.7.1 (tried both alternative firmwares with same issue):

URL filter works as expected but introduces a strange issue. Enable the filter and it blocks unrelated https traffic, but only on IE ( 7 and 8 ) on XP. IE on later MS OS unaffected, firefox on XP unaffected. Disable URL filter and problem disappears. I've tried resetting the router and configuring the minimum required to test, ie net access and URL filter, taking out all VPN, port forwarding settings etc with no joy. Is this a known issue? Misconfiguration?
Yet to try reverting to older firmware and don't know if problem existed with original.

This would actually be a problem on the XP machine as the https traffic should of been encrypted and the router unable to block it!

In short; you cannot use the URL filter to block https traffic as it is encrypted at the application layer. This means that the URL is hidden by the time the router gets it.

I think you may have misread my post. I'm not trying to block https traffic. If I enable ANY URL filter, as a side effect ALL https traffic is blocked on IE on XP. Switch off URL filter and it returns to normal. Tested on 3 XP machines. It's a router issue not a PC issue.

My bad, this might well be a bug related to the OS/browser. Dont have any XP machines lying about to test... Anyone else?

Reverted to 3.3.5.2_232201 and all is well.

The_latest_firmware_is_not_always_the_best!