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N_67263's avatar
N_67263
Icon for Nimbostratus rankNimbostratus
Aug 28, 2017

iRule which strips of the domain name and replaces that with another domain name.

Team, Can anyone help me with an iRule which strips of the domain name and does a DNS query with some other domain name? e.g. The F5 intercepts a request on "xyz.externaldomain.com". F5 strips of the...
application delivery
iRules
  • Yann_Desmarest_'s avatar
    Yann_Desmarest_
    Aug 28, 2017

    Hi,

    Maybe the following irule may help you :

    when HTTP_REQUEST {
    if { [HTTP::host] contains "xyz.externaldomain.com" } {
        HTTP::header replace Host "xyz.internaldomain.com"
    }
}

    You may also use 

    string map
    command to make the replacement more dynamic

Stanislas_Piro2's avatar
Stanislas_Piro2
Icon for Cumulonimbus rankCumulonimbus
Aug 30, 2017

Hi,

You can define which dns server is used for DNS requests.

If you want to manage DNS servers, create a LTM pool including dns servers with dns monitor and use this irule. the dns pool name in this irule is 

p_dns

when CLIENT_ACCEPTED {
        foreach dns [active_members -list p_dns] {   
         Check if the first list element was empty
        if {[set dest [lindex [RESOLV::lookup @[lindex $dns 0] -a "www.abc.com";] 0]] ne ""} {
             Set Node IP based on DNS resolution
            node $dest 443
            break
        }
    }
}