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eightsixstud_29's avatar
eightsixstud_29
Icon for Nimbostratus rankNimbostratus
Sep 15, 2016
Solved

Error using iRule for Conditional DNS Lookups

I am looking to perform some DNS lookups on a domain and based on the results, either provide the client with the external IP if it exists or the internal IP if there isn't an external A record.   ...
application delivery
BIG-IP DNS
iRules
  • Samir_Jha_52506's avatar
    Samir_Jha_52506
    Sep 15, 2016

    HI,

    Can you please try below irule.

       when DNS_REQUEST {
    if { ([IP::addr [IP::client_addr] equals 192.168.1.0/24]) and ([DNS::rrname] contains "test.com") } {
                        set dnsName [RESOLV::lookup @8.8.8.8 -a [DNS::rrname]] 
                        if { ([DNS::rrtype] equal "A") } {
                            DNS::return
                        } 
        }
    }
R_Marc's avatar
R_Marc
Icon for Nimbostratus rankNimbostratus
Sep 15, 2016

Not sure how relevant this is, but for me, I had to create a local virtual to get Resolve to work consistently. Going direct actually caused all DNS to stop working on the box (TMos and Linux).

[RESOLV::lookup @/Common/dns-proxy-ipv4-dns-virtual -a $name]