Chapter 6 Deploying Wireless Networks for FortiOS 5.0 : Configuring wireless network clients : Troubleshooting : Checking that the client has received IP address and DNS server information : Mac OS
  
Mac OS
1. From the Apple menu, open System Preferences > Network.
2. Select AirPort and then select Configure.
3. On the Network page, select the TCP/IP tab.
4. If there is no IP address or the IP address starts with 169, select Renew DHCP Lease.
5. To check DNS server addresses, open a terminal window and enter the following command:
cat /etc/resolv.conf
Check the listed nameserver addresses. A network for employees should us the wired private LAN DNS server. A network for guests should specify a public DNS server.