Configure server availability monitoring

There are different methods for monitoring whether a server or a service running on a server is available.

For more details about the product and how to configure features, click Help or press F1.

Steps

Select Configuration, then browse to SD-WAN.
Browse to Traffic Handlers.
Right-click a Server Pool element, then select Properties.
Select the Monitoring tab.
In the Frequency Check field, define how often you want the availability to be checked.
From the Method drop-down list, select the method for monitoring the availability of the servers in the Server Pool.
(TCP or HTTP methods) Specify the additional options.

The text in the Request field is sent by the firewall in the first packet after the TCP handshake. The text in the Response field is checked against the first data packet received from the server after the TCP handshake.

Tip: The response is evaluated using a begins with pattern. It is not necessary to enter the complete text of the response.

When using TCP, if the Request and Response fields are left empty, the Firewall only checks that a connection can be established.

For example, to check for the HTTPS service, enter 443 as the port number, but leave the Request and Response fields empty. In this case, the firewall only checks that a connection to port 443 can be established.
Click OK.

Use this dialog box to define Server Pools.

Option	Definition
General tab
Name (Optional)	Specifies the Server Pool name.
Category	Categories allow you to flexibly filter your Management Client view.
Select (Optional)	Opens the Category Selection dialog box.
Comment	An optional comment for your own reference.

Option	Definition
External Addresses section
NetLink	Specifies the NetLink you want to use.
IP Address	Specifies the external NATed destination IP address for the Server Pool.
Status	Shows the NetLink status: Enabled or Disabled. Enabled NetLinks are used in the Server Pool.
Proxy ARP Entry	When enabled, automatically generates a proxy ARP for the NATed address in the selected Network.
Add	Opens the External Address dialog box.
Edit	Opens the External Address dialog box and allows you to change the settings for the selected NetLink.
Remove	Removes the selected external address.
Enable Dynamic DNS Updates	Enables Dynamic DNS Updates from the Server Pool to the DNS Server.
DNS Server	Select the External DNS Server element to which the DDNS updates are sent.
Fully Qualified Domain Name	Enter the Fully Qualified Domain Name for the Server Pool service (for example, “www.example.com”).

Option	Definition
Server Pool Members section
Element	Shows the names of the elements selected as pool members.
IP Address	Shows the IP addresses of the elements selected as pool members.
Up	Moves the element up the list.
Down	Moves the rule position down the list.
Add	Opens the Select Element dialog box.
Remove	Removes the selected element from the Server Pool Members list.
Allocate Traffic to Servers by	Select the granularity for the server selection (defines how likely it is that traffic is redirected to a particular server). Usually it is best to choose the least granular option that still produces an acceptable distribution of traffic. The options are (from least granular to most granular): Not Defined — Not Defined has the same effect as the Source Network option. Source Network — Source Network directs traffic coming from the same C-class network to the same server. This option is a good choice when connections come from many different networks. Host — Host directs traffic coming from the same IP address to the same server. This option is a good choice when a large portion of connections come from different hosts in the same C-class network. Connection — Connection makes a new traffic management decision for each new connection. This choice might be necessary if a large portion of connections uses just one IP address. Order — Allocate Traffic based on the order of the elements on the list.

Option	Definition
Monitoring tab
Frequency Check	Specifies how often you want the availability to be checked.
Method	Specifies the method for monitoring the availability of the servers in the Server Pool. Ping — Uses ICMP echo request (ping) messages to monitor the availability of the servers. Agent — Uses the Server Pool Monitoring Agent feature. Before enabling this method, make sure that you have installed and configured the Monitoring Agents on all servers. TCP — Checks that a specific TCP service is available. HTTP — Checks that the HTTP service is available.

Option	Definition
When Method is Agent
Port	Defines the port number.

Option	Definition
When Method is TCP
Port	Defines the port number.
Request (Optional)	Specifies the string of ASCII text that the firewall sends.
Response (Optional)	Specifies the string of ASCII text that you expect to receive.

Option	Definition
When Method is HTTP
Port	Defines the port number.
Path	Specifies the path to the webpage.
Host Header (Optional)	Specifies the host name of the web server.
Response (Optional)	Specifies the string of ASCII text that you expect to receive.