DHCP

If you are using dial-up or a broadband connection with a non-static IP address, your ISP may use DHCP to allocate and periodically renew your IP address. To configure ZoneAlarm Pro to allow DHCP renewal, do the following:

1. Add your ISP's DHCP servers to the Trusted Zone, or (if the DHCP server is in a different subnet from your computer) add your gateway to the Trusted Zone.( If you get your DHCP from your own local network (e.g. from a Linksys router), make sure the DHCP source is included in the Trusted Zone. If you you have added your local network to the Trusted Zone, this is already done).
   

Tip If your ISP uses multiple DHCP servers, it may be easiest to add them to the Trusted Zone by host name rather than by IP address.

2. Allow DHCP and DHCP broadcast/multicast in the Trusted Zone.
3. Make sure the security level for the Trusted Zone is medium, and that DHCP and broadcast/multicast are allowed in the Trusted Zone at medium security.

To learn how to set the security level, add elements to the Trusted Zone, and allow protocols, see Related Topics.

If you are still having connection problems after following the steps above, contact your ISP's customer support staff.

Related Topics

Setting the Trusted Zone security level
Blocking and unblocking ports
Adding to the Trusted Zone

Glossary

DHCP (Dynamic Host Configuration Protocol)
A protocol used to support dynamic IP addressing. Rather than giving you a static IP address, your ISP may assign a different IP address to you each time you log on. This allows the provider to serve a large number of customers with a relatively small number of IP addresses.

DHCP (Dynamic Host Configuration Protocol) broadcast/multicast
A type of message used by a client computer on a network that uses dynamic IP addressing. When the computer comes online, if it needs an IP address, it issues a broadcast message to any DHCP servers which are on the network. When a DHCP server receives the broadcast, it assigns an IP address to the computer.