Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 192)

176 Brocade Virtual ADX Server Load Balancing Guide
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Layer 7 health checks
4
SSL (simple)
The Brocade Virtual ADX sends an SSL client hello with the SSL SID set to 0:
• If the server responds, then the Brocade Virtual ADX resets the connection and marks the port
ACTIVE.
• If the server does not respond, the Brocade Virtual ADX retries the health check up to the
number of times configured (the default is two retries). If the server still does not respond, the
Brocade Virtual ADX marks the server port FAILED and removes the server from the
load-balancing rotation for SSL service.
Performed:
• Immediately following a successful Layer 4 TCP health check
• At regular intervals, if keepalive is enabled for the port
Telnet
The Brocade Virtual ADX waits for a message from the Telnet server:
• If the server sends a command string that starts with the IAC escape characters (“FF”), the
Brocade Virtual ADX resets the connection and marks the port ACTIVE.
• If the server does not send a command that starts with the IAC escape character, the Brocade
Virtual ADX retries the health check up to the number of times configured (the default is two
retries). If the server still does not send the expected escape character, the Brocade Virtual
ADX marks the server port FAILED and removes the server from the load-balancing rotation for
Telnet service.
Performed:
• Immediately following a successful Layer 4 TCP health check
• At regular intervals, if keepalive is enabled for the port
Port-specific settings for Layer 7 health checks
You can configure the following Layer 7 health check parameters on a real server basis:
• Keepalive health check state (enabled or disabled)
• HTTP keepalive method, values, and valid status codes
• HTTP content matching lists for HTTP content verification health checks
• Scripted health checks (content verification health checks for unknown ports)
• DNS keepalive method and values (zone-based or addressed-based check and the zone or
domain name)
• RADIUS keepalive values (user name, password, and encryption key)
• LDAP version (2 or 3)