Brocade Communications Systems ServerIron ADX 12.4.00 - Manual (Page 200)

188 ServerIron ADX Global Server Load Balancing Guide
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GSLB error handling for unsupported DNS requests
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• The final two GSLB messages in this example (the ones nearest the top of the log) indicate that
the site ServerIron ADXs responded to the Layer 3 health check (IP ping).
Disabling and re-enabling traps
All traps, including GSLB traps, are enabled by default.
To disable a GSLB trap, enter a command such as the following:
ServerIronADX(config)# no snmp-server enable traps l4-gslb-remote-si-down
The command in this example disables the trap that occurs if a remote site ServerIron ADX fails its
Layer 3 health check and its status therefore changes from “up” to “down”.
Syntax: [no] snmp-server enable traps <trap-type>
For GSLB, the trap type can be one of the following:
• l4-gslb-remote-gslb-si-down: Generated when the GSLB protocol connection from this site
ServerIron ADX to a remote GSLB ServerIron ADX goes down.
• l4-gslb-remote-gslb-si-up: Generated when the GSLB protocol connection from this site
ServerIron ADX to a remote GSLB ServerIron ADX comes up.
• l4-gslb-remote-si-down: Generated when the GSLB protocol connection from this GSLB
ServerIron ADX to a remote site ServerIron ADX goes down.
• l4-gslb-remote-si-up: Generated when the GSLB protocol connection from this GSLB ServerIron
ADX to a remote site ServerIron ADX comes up.
• l4-gslb-health-check-ip-down: Generated when GSLB determines that the IP address belonging
to a domain name for which the ServerIron ADX is providing GSLB is down.
• l4-gslb-health-check-ip-up: Generated when GSLB determines that the IP address belonging to
a domain name for which the ServerIron ADX is providing GSLB is now active.
• l4-gslb-health-check-ip-port-down: Generated when an application port in a domain on the site
IP address fails its Layer 4 TCP or UDP health check, resulting in a status change to “down”.
• l4-gslb-health-check-ip-port-up: Generated when an application port in a domain on the site IP
address passes its Layer 4 TCP or UDP health check, resulting in a status change to “up”.
GSLB error handling for unsupported DNS requests
The ServerIron ADX can perform GSLB on client queries for the following DNS record types:
• IPv4 address records (A records)
• Canonical Name records (CNAME records)
In many GSLB topologies, the GSLB ServerIron ADX front-ends a DNS server. When the GSLB
ServerIron ADX receives a client query for supported DNS record types, the GSLB ServerIron ADX
forwards the client query to the DNS server. In turn, the DNS server sends a response to the GSLB
ServerIron ADX, which performs GSLB on the response, then forwards the response to the client.
Similarly, when the GSLB ServerIron ADX receives a client query for unsupported DNS record types,
such as IPv6 address records (AAAA records), Name Server records (NS records), or Mail Exchange
records (MX records), the GSLB ServerIron ADX forwards the client query to the DNS server. The
DNS server sends a response to the GSLB ServerIron ADX, which then forwards the response,
unaltered, to the client.