Using Client Subnet in DNS Requests
BIG-IP DNS 14.0 now supports edns-client-subnet (ECS) for both responding to client requests (GSLB) or forwarding client requests (screening). The following is a quick start on using this feature.
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Published Sep 14, 2018
Version 1.0
Eric_Chen
Employee
EmployeeEric_ChenEmployee
Employee
Hao_Admin
Nimbostratus
NimbostratusI want to insert 'client subnet' in 'add OPT', The purpose is to display the source IP address in the real DNS Server log file, So use the following iRules script：
when DNS_REQUEST {
DNS::edns0 subnet address [IP::client_addr]
DNS::edns0 subnet source 32
}
Now through packet capture, the request data packet received by SLB can display the effect of inserting the 'client_addr' field into 'add OPT'.
But, when the backend server sends back the package, it displays' Flags: 0x8101 Standard query response, Format error ', Failed to resolve the A record of the domain name,
So, do you have any good ideas to rule out this problem? Thanks!