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Forum Discussion

Mui_64918's avatar
Mui_64918
Icon for Cirrus rankCirrus
Feb 20, 2014

Dynamic Pool Members with DNS resolution

Has anyone tried to route traffic to a pool member using DNS name instead of IP address? Either resolve the name then check the IP/Node if its active and then send traffic. If we were to talk to oth...
application delivery
devops
iRules
LTM
nitass's avatar
nitass
Icon for Employee rankEmployee
Feb 23, 2014

as JPV mentioned, you can use RESOLV::lookup and node command.

e.g.

 config

root@(ve11a)(cfg-sync In Sync)(Active)(/Common)(tmos) list ltm virtual bar
ltm virtual bar {
    destination 172.28.24.10:80
    ip-protocol tcp
    mask 255.255.255.255
    profiles {
        http { }
        tcp { }
    }
    rules {
        myrule
    }
    source 0.0.0.0/0
    source-address-translation {
        type automap
    }
    vs-index 14
}
root@(ve11a)(cfg-sync In Sync)(Active)(/Common)(tmos) list ltm rule myrule
ltm rule myrule {
    when HTTP_REQUEST {
  set host [HTTP::host]
  set dest [lindex [RESOLV::lookup @8.8.8.8 -a [HTTP::host]] 0]
  if { $dest ne "" } {
    node $dest
  } else {
    HTTP::respond 503
  }
}
when HTTP_RESPONSE {
  log local0. "client [IP::client_addr]:[TCP::client_port] server [IP::remote_addr]:[TCP::release] host $host"
}
}

 /var/log/ltm

[root@ve11a:Active:In Sync] config  tail -f /var/log/ltm
Feb 23 00:37:05 ve11a info tmm[4068]: Rule /Common/myrule : client 172.28.24.1:39112 server 206.190.36.45:0 host www.yahoo.com
Feb 23 00:37:13 ve11a info tmm1[4068]: Rule /Common/myrule : client 172.28.24.1:39113 server 74.125.200.99:0 host www.google.com
Feb 23 00:37:20 ve11a info tmm[4068]: Rule /Common/myrule : client 172.28.24.1:39114 server 64.4.11.42:0 host www.microsoft.com