Craig Sanders <cas@taz.net.au> wrote:
1. buy a USB/PCI/PCI-e wireless NIC and install it in your current gateway box.
you already have dhcp, dns, iptables, and everything else configured and running, so you only need to configure hostapd.
be careful when selecting a NIC, not all will work in Master aka AP or Access Point mode - although it's not uncommon for 802.11a/b/g. unfortunately, very few 802.11n NIC drivers support master mode in linux. NICs based on the ath9k[2] chip seem to be the best bet for 802.11n. The brcmsmac[3] driver also got AP mode support in March this year.
Thanks. In the end, I wasn't satisfied with the USB options available, but the other option - a PCI-Express card - is still possible if I can find one that I know for sure has a supported Atheros controller suitable for hostAP. There's one free PCI-Express slot left, specified as "x8 mechanical/x4 electrical", which I understand will take any lower (e.g., x2) card.
https://help.ubuntu.com/community/WifiDocs/MasterMode http://en.wikipedia.org/wiki/Comparison_of_open-source_wireless_drivers#Driv...
2. get a cheap old laptop with built-in wireless NIC. Again, make sure that the NIC supports Master mode under linux. Configure hostapd. if you use a separate IP subnet for the wireless LAN, you may also need to run a dhcp relay so that bootp packets get forwarded between the wlan and your dhcp server (alternatively, just run another dhcp server on the laptop, listening only on the wlan interface so it doesn't conflict with your main dhcp server)
It's unfortunate that my current laptop can't do this, even as a temporary solution, as the Intel wireless controller does not support master mode even under the most recent drivers.