Okay, so I've been battling with this for a little while and although my mac knowledge is good, my network knowledge is not so. I'll give you our set up and then the issue. In the house we have 2 Airport Extremes and 2 Airport Expresses. There is also an ethernet cable that runs through the wall from one end of the house to the other. The 2 Expresses are connected to hi fis to create airplay speakers. Our internet connection comes through in the back room and goes into our modem and then into the primary Airport Extreme (let's call this AE1, this is a 5th gen). There is an ethernet connection from this running to the secondary AE (AE2, which is a 3rd gen). There are then 2 Airport Expresses in the house. These are both model number MB321LL/A which i believe are 1st gen? I'm not entirely sure. These are both located nearer to AE2 than AE1 however I want them to extend AE1 as this is a better quality product? Is this right? The reason is that I have tried setting this network up a few times and after about a week, the 2 AEx start flashing with an orange light stating that they can't extend the network. What I think is happening is that they are extending the secondary AE which is an extension of AE1 and I don't know if this is possible. AE2 is set up in bridge mode and to just extend AE1 but due to it's location it has a lot more devices connected to it (iPhones, Macs, iPads etc). Would it be advisable to swap the 2 AExtremes? Is there something fundamentally wrong with my setup? One option is i could just remove the second Airport Extreme from the network entirely but I don't see why I should have to do this. I would ideally like to keep this in place. If you have any suggestions or would like more info about the network or settings I have in place please reply and I'll let you know. I'm sure someone out there knows the answer, or has done something similar previously, I just haven't found it yet.