FAILED selecting pool based on DNS reverse lookup result.

Hi, nitass, thank you for your answer!

I tried below:

when CLIENT_ACCEPTED {
    NAME::lookup @DNS_SERVER_IP [IP::client_addr]
    node 172.17.20.104:8080        down node
}

when NAME_RESOLVED {
    set ptr [string tolower [NAME::response]]
    log local0. "[IP::client_addr]:[TCP::client_port]: Lookup result: $ptr"
    if { $ptr ends_with ".jp" } {
        set pool_name SMTP_AUTH_Pool
    } else {
        set pool_name SMTP_Fallback_Pool
    }
}

when LB_FAILED {
    log local0. "LB_FAILED triggered."
    LB::reselect pool $pool_name
}

when SERVER_CONNECTED {
    log local0. "SERVER_CONNECTED triggered. Pool is $pool_name."
}

It worked!! but sometime it failed, and logged below.

Apr 17 09:00:05 local/tmm1 err tmm1[5277]: 01220001:3: TCL error: dns_reverse_lookup_test  - can't read "pool_name": no such variable     while executing "LB::reselect pool $pool_name"

I think it is due to the timing of processing NAME_RESOLVED and LB_FAILED. If NAME_RESOLVED is processed earlier than LB_FAILED, it succeeds, but if NAME_RESOLVED is processed after than LB_FAILED, it fails.

I think it seems that our BIGIP should be upgraded to non-affected version to use RESOLV::lookup.

Thanks so much, nitass!