User's Manual

Health Check
DNS Servers
This field allows you to specify two DNS hosts’ IP addresses with which
connectivity is to be tested via DNS lookup.
If Use first two DNS servers as Health Check DNS Servers is checked, the first
two DNS servers will be the DNS lookup targets for checking a connection's
health. If the box is not checked, Host 1 must be filled, while a value for Host 2 is
optional.
If Include public DNS servers is selected and no response is received from all
specified DNS servers, DNS lookups will also be issued to some public DNS
servers. A WAN connection will be treated as down only if there is also no
response received from the public DNS servers.
Connections will be considered as up if DNS responses are received from any one
of the health check DNS servers, regardless of a positive or negative result. By
default, the first two DNS servers of the WAN connection are used as the health
check DNS servers.
Health Check Method: HTTP
HTTP connections will be issued to test connectivity with configurable URLs and strings to match.
URL1
WAN Settings>WAN Edit>Health Check Settings>URL1
The URL will be retrieved when performing an HTTP health check. When String
to Match is left blank, a health check will pass if the HTTP return code is between
200 and 299 (Note: HTTP redirection codes 301 or 302 are treated as failures).
When String to Match is filled, a health check will pass if the HTTP return code is
between 200 and 299 and if the HTTP response content contains the string.
URL 2
WAN Settings>WAN Edit>Health Check Settings>URL2
If URL2 is also provided, a health check will pass if either one of the tests passed.
Other Health Check Settings
Timeout
This setting specifies the timeout in seconds for ping/DNS lookup requests. The
default timeout is 5 seconds.
Health Check
This setting specifies the time interval in seconds between ping or DNS lookup