Retain the URL on Browser

eagertolearn The following iRule should be what you want. I did not put "XYZ" in capitalized letters because I believe the RFC states that the host section will always come across as lower case.

when CLIENT_ACCEPTED priority 500 {

    set DEFAULT_POOL [LB::server pool]

}

when HTTP_REQUEST priority 500 {

    if {[string tolower [HTTP::host]] == "123.abc.com" } {

        HTTP::host [string map {"abc" "xyz"}[HTTP::host]]
        pool ${DEFAULT_POOL}

    }

}