Issue with configuring Guest network on Apple Airport Express Units
Recently we setup a wireless network using Apple Airport Express Basestation units with the requirement that there had to be a separate guest network. Now this should be straight forward as the guest network feature is built in and the steps required are explained here by Apple - https://support.apple.com/en-gb/HT204590
However this did not work as smoothly as Apple explain on their site and yet the solution is very quick and easy!
So the techy bit - the previous setup was just a Virgin Media Super Hub that acted as the modem, resolved all DNS and acted as the DHCP server. Your basic router setup designed to run your whole network. (Let's give it the IP address 192.168.0.1) - but now we wanted to add the Airport Express units. This is straight forward when a guest network is not required as a new wireless network can be setup on the basestations without changing anything on the existing router. However the requirement is for a guest network which means that there needs to be a DHCP server that gives out IP addresses on a separate IP range than the main network - so when following the guide by Apple they instruct you to turn on DHCP and NAT on the main Airport Express unit which allows the IP range to be set on both the main wireless and the guest network. Simple right? Not quite. An error will come up stating that you can't set the IP range given out by DHCP on the Airport Express as 192.168.0.* because it recognizes that the Virgin Media router is acting as DHCP giving out IP addresses on the same IP range. If you set the range to 192.168.1.* for example the setting will save however the Airport Express unit will be unhappy (flashing amber) because there is another DHCP server on the network (the Virgin Router) and anything plugged into the router will be on a separate IP range to anything connected to the Airport Express units meaning devices will not be able to communicate.
So the simple bit - The one step Apple failed to mention in their article is that for a lot of users they will simply need to set their previous router to modem mode only. This means that the router simply passes all broadband traffic through to the Airport Express unit and the basestation will manage everything else on the network.
When configuring networks there is never one way to do things as there are so many different configruaitons and equipment that could be in use and requirements to fullfill, so whilst Apple's instructions might be helpful to some users with a particular setup it wouldn't hurt them to give a bit more detail or context in their articles!
Do you need help setting up or impoving your wireless network? Let Qdos help.