I've updated to Mountain Lion, and I'm having some DNS problems. I always PPTP/L2TP VPN connections on my macbook. Recently after a while of working with Mountain Lion, VPN stops sending and receiving data and I have to disconnect/connect again to make it work again. I'm not having the same problem with iPad, iPhone and PC.
and without the VPN, when I try pinging 126.96.36.199 , 188.8.131.52 and other DNSs and all I get is timeouts! But the ping works fine on my other devices. I also tried setting the DNS to Google and OpenDNS DNSs (184.108.40.206, 220.127.116.11, 18.104.22.168, ...) but it still didn't help. I also tried emptying DNS cache and other solutions. but nothing.
I'm guessing that these two problems are tied together. Any solutions?