The best way howto check internet connection every second or less?
 

Hello,

I have a router with wwan conections and I need to show to the clients cached page with custom message or custom error page when the requested page is not cached when there is no internet connection (the connection is usually not available few seconds or less). I have installed WWWOFFLE which is working really great. I am redirecting all requests to WWWOFFLE via iptables. The problem is that it needs to be switched to offline/online mode manually with cmd. The second problem is in DNS because when browser didnt receive correct answer from DNS it shows their custom error page instead the one from proxy. To avoid this I am creating fake DNS records using BIND when the connections is not available which point everything to the router IP. It works also good. The questions is whats the best way howto switch proxy to offline mode and create fake dns zone in a very short time when there is no internet connection (is there some better way to test internet connection then ping)? Or is there a better solution howto display cached pages and/or custom error page when wwan connection is temporally not available due to GSM low signal? I dont want clients to setup proxy manually in their browser. Thank You