SurferTim:
If your code uses dns to resolve the domain name of the server, the dns server is not localnet, and the dsl is down, that code will never connect. If the internet part is down, the length of the delay will not matter. If your code can't connect, it can't connect.
Thanks SurferTim
The setup in my code contains :
char serverName[] = "http://www.abc.com";
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; //physical mac address
IPAddress ip(192,168,1,101); // ip in lan
IPAddress gateway(192,168,1,254); // internet access via router
IPAddress subnet(255,255,255,0); //subnet mask
IPAddress myserver(11,11,18,70); //my web server ip
EthernetServer server(82); //server port
EthernetClient client;
String readString;
Ethernet.begin(mac, ip, subnet, gateway);
server.begin();
but I think maybe I have not made my question clear.
So here it is re-worded : is there any way to check if a dsl connection exists, that is not subject to any time delays / timeouts, or any way to ping a server with a set maximum timeout ? That way I could ping my web server first, and if that does not respond within, for example, 100ms, then assume that the dsl line is down ( or the web server is down ) and move on with the rest of the sketch without wasting time ( and delaying sketch code execution ) waiting for the connection to time-out ?