ISP heartbeat

Most ISPs periodically send "heartbeat" messages to their connected dial-up customers to make sure they are still there. If it appears a customer is not there, the ISP might disconnect her so that her IP address can be given to someone else.

By default, ZoneAlarm Pro blocks the protocols most commonly used for these heartbeat messages, which may cause you to be disconnected from the Internet.

If this happens you can solve the problem in any of the three ways described below.

Identify the server sending the message and add it to your Trusted Zone.

This is the preferred solution, because it will work whether your ISP uses NetBIOS or ICMP to check your connection, and it allows you to maintain high security for the Internet Zone. To identify the server your ISP uses to check your connection, follow these steps:

1. Wait until your ISP disconnects you.
2. Go to the Alert Log tab (Alerts & Logs panel).
3. In the alerts list, find the alert that corresponds to the time you were disconnected.

If you're not able to identify the server this way, contact your ISP. They should be able to tell you what servers your need to allow.

After you have identified the server, add it to the Trusted Zone. How?

Allow ping messages through the Internet Zone.

If your ISP uses ICMP echo (or ping) messages for connectivity checks, use the Internet Zone tab (Custom Securities dialog box) to configure ZoneAlarm Pro to allow ping messages from the Internet Zone. To do this:

1. Go to the Main tab in the Firewall Panel.
2. In the Internet Zone section, click Custom
3. Select check box labeled Allow incoming ping (ICMP echo).
4. Click OK.

Set the security level for the Internet Zone to medium.

The quickest but least secure solution is to reduce the security level for the Internet Zone to medium. How?

To learn more about the medium security setting and how it protects you, see the related topic, Security levels.

Related Topics

Internet Zone tab (Custom Securities dialog box)
Security levels
Setting Internet Zone security to medium

Glossary

ISP (Internet Service Provider)
A company that provides access to the Internet. ISP's provide many kinds of Internet connections to consumers and business, including dial-up (connection over a regular telephone line with a modem), high-speed Digital Subscriber Lines (DSL), and cable modem.

dial-up connection
Connection to the Internet using a modem and an analog telephone line. The modem connects to the Internet by dialing a telephone number at the Internet Service Provider's site. This is in distinction to other connection methods, such as Digital Subscriber Lines, that do not use analog modems and do not dial telephone numbers.

NetBIOS (Network Basic Input/Output System)
A program that allows applications on different computers to communicate within a local network. By default, ZoneAlarm Pro allows NetBIOS traffic in the Trusted Zone, but blocks it in the Internet Zone. This enables file sharing on local networks, while protecting you from NetBIOS vulnerabilities on the Internet.

ICMP (Internet Control Messaging Protocol)
An extension of the Internet Protocol that supports error control and informational messages. The "ping" message is a common ICMP message used to test an Internet connection.

ping
A type of ICMP message (formally "ICMP echo") used to determine whether a specific computer is connected to the Internet. A small utility program sends a simple "echo request" message to the destination IP address, and then waits for a response. If a computer at that address receives the message, it sends an "echo" back. Some Internet providers regularly "ping" their customers to see if they are still connected.