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 184.108.40.206 , 220.127.116.11 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 (18.104.22.168, 22.214.171.124, 126.96.36.199, ...) 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?