LTM logs filled with err tmm1[11650]: 01220001:3: TCL error: /Common/HttpOnly_Secure_irule <http_response> - Operation not supported (line 1)

Hi kohli9harjeev,

your code looks good to me.

The error message will most likely occour if the current HTTP-request was "somehow" already responded by previous iRules. To check this behavior you could modify your code to...

when HTTP_RESPONSE { 
    set cookie_value [HTTP::header values "Set-Cookie"] 
    if { $cookie_value ne ""} then {
        if { [catch {HTTP::payload replace 0 0 {}}] } then {
            log -noname local0. "Warning: The HTTP request is already responded. So the next command will create an exception!" 
        }
        HTTP::header remove "Set-Cookie"
        foreach set_cookie_header $cookie_value { 
            HTTP::header insert "Set-Cookie" "${set_cookie_header};Secure;HttpOnly" 
        }
    }
}

Cheers, Kai