cURL and Proxy Servers

Hello everyone, I'm using cURL and have a question about this line (part of a function) curl_setopt($ch, CURLOPT_PROXY, $proxy2use); I know that *after* I curl_exec() i can find out if the proxy resolved or not with curl_errno() (it would return 5) but it seems that if it does fail to resolve, it will default to the users IP This is not acceptable ;-) I already check that the proxy is up and i can connect to it prior to running my curl function, but if the proxy still doesnt resolve, how might i prevent the curl function form executing? Much thanks for any insight on this... -- Nick W