Have you ever came a cross on limited or no connectivity errors in a network when you try to request for a DHCP IP.
I was encountering this issue on few computer while connected to gateway which is a Juniper SSG 5 firewall.
One of the possibility this can happen is due to the number of DHCP host specify in the DHCP setting has been used.
You may follow the steps provided below to solve this issue.
1. Login to the Juniper SSG5 firewall.
2. Go to the main menu and select Network.
3. Once see the Network menu, select DHCP on your left and choose the network which you want to change.
4. Go to the Addresses option on the below page.
4. Increase the number of network host that needs DHCP. Alternatively you can also specify the lease day. This will ensure the DHCP IP will be only available till the day specified.