Brocade Virtual ADX Global Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 33)

Brocade Virtual ADX Global Server Load Balancing Guide 23
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Proxy for DNS server
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Configuring HTTP health check parameters
For HTTP hosts, you also can customize the health check by changing the URL method and the
string requested by the Brocade Virtual ADX, as well as the HTTP status codes the Brocade Virtual
ADX accepts as valid responses. By default, the Brocade Virtual ADX performs the HTTP health
check as follows:
• The Brocade Virtual ADX sends a HEAD request for the default URL string, “HEAD /”.
• If the server responds with the status code 401 or a code in the range 200 to 299, the server
passes the health check.
You can change the request method from HEAD to GET. In addition, you can change the URL string
the Brocade Virtual ADX requests from the server and the status codes that the Brocade Virtual
ADX accepts as valid responses for passing the health check.
The commands in the following example change the method from HEAD to GET and to add 404 as
a valid status code response to the health check.
Virtual ADX(config)#gslb dns zone brocade.com
Virtual ADX(config-gslb-dns-brocade.com)#host-info www http url "GET /index.htm"
Virtual ADX(config-gslb-dns-brocade.com)#host-info www http status-code 200 299
401 401 404 404
Syntax: host-info host-name http | TCP-portnum url “[GET | HEAD] [/]URL-page-name
GET or HEAD is an optional parameter that specifies the request type. By default, HTTP keepalive
uses HEAD to retrieve the URL page. You can override the default and configure the Brocade Virtual
ADX to use GET to retrieve the URL page.
The slash ( / ) is an optional parameter. If you do not set the GET or HEAD parameter, and the slash
is not in the configured URL page, then Brocade Virtual ADX automatically inserts a slash before
retrieving the URL page.
Syntax: host-info host-name http | TCP-portnum status-code range [range [range [range]]]
You can specify up to four ranges (total of eight values). To specify a single message code for a
range, enter the code twice. For example to specify 200 only, enter the following command: port
http status-code 200 200.
NOTE
When you change the status code ranges, the defaults are removed. As a result, you must specify
all the valid ranges, even if a range also is within the default ranges. For example, if you still want
codes 200 to 299 to be valid, you must specify them.
NOTE
When a URL string is associated with a TCP port number rather than the well-known HTTP port, the
Brocade Virtual ADX performs both a TCP and an HTTP health check. In this case, you must specify
the method and URL before specifying the status code ranges. The software displays an error
message if you accidentally try to change the status codes before specifying the method and URL.
Configuring DNS domain name aliases
You can configure an alias for a domain name and application configured on the GSLB Brocade
Virtual ADX. This feature is useful together with the DNS cache proxy feature when you want the
GSLB Brocade Virtual ADX to learn a set of proxy server IP addresses for a domain, then respond to
client requests with the best proxy server address.