I use only the WAN interface on my Antminers, and leave it with fixed IP which is set to a different value for each Antminer S1. All these fixed IP addresses are within the range supported by my router, and do not conflict with other devices. I read many posts by people who got their Antminer S1's into trouble by trying to use the LAN interface, bridging it with the WAN and all sorts of other combinations. Note that WAN means "Wide Area Network" (NOT "Wireless").
Why use a fixed IP? - because it removes the variability of different IP every time you cycle power on your Antminer and removes the issue of DHCP lease expiry (DHCP grants a 'temporary' IP address which expires after some set time, which may cause connection loss).
While some people managed to use their Antminer's with the WiFi, there are also many who reported issues with that, so a wired network connection is the preferred way to go.
Follow one of the setup guides such as https://bitcointalksearch.org/topic/guide-dogies-comprehensive-bitmain-antminer-s1-setup-hd-355387 or https://bitcointalksearch.org/topic/setup-troubleshoot-bitmain-antminer-s1-180ghs-miner-344970
Cheers