If I get Internet access via a MiFi device, how should I connect to it from a PC running OpenWrt which has a LAN and WiFi interface? I would like the PC to act as a gateway for the LAN.
Presumably the WiFi interface would use DHCP and the LAN would have a static IP address.
Do I need to bridge the two interfaces? Apologies, as I'm a little hazy how this can be achieved...
A default OpenWrt install has two networks already set up, wan and lan, with rules to route and firewall between them. In a device like a PC that only has one Ethernet port, that port is attached to the LAN and nothing attached to WAN. So attach the MiFi to the WAN network using a wifi client. This wifi client must be the only thing in the WAN. The default is for WAN to request DHCP from the ISP (the MiFi in this case). All users will route to it from the LAN network.
Depending on your wifi card and driver's capabilities, you may also be able to set up a wifi AP (on the LAN) for wireless users.