I have several devices on the network. Only one with a problem is this Ubuntu 12.04 machine. Its not a big problem and it is infrequent. So far, I have not noticed a particular cause/event.
At some point, I'll have no Internet connection. LAN is fine. I can SSH to the machine (I only have SSH access. Its headless). It can ping other LAN devices but no external devices. All other devices can ping it, and they can also ping external no problem.
Rebooting fixes (until the next time).
Its not the firewall... shut it off = no resolution.
I'm not really sure where to begin with diagnosing.
If I can't "fix" the problem... I'd settle for a command that can resolve without rebooting. Can I "refresh" the Internet connection?
Oh... this is a wired connection (Realtek GbE LAN chip).
edit: OK, happened again. Here is the output from "ip route show"
default via 10.1.0.5 dev tun0 proto static
10.1.0.1 via 10.1.0.5 dev tun0 proto static
10.1.0.5 dev tun0 proto kernel scope link src 10.1.0.6
169.254.0.0/16 dev eth0 scope link metric 1000
174.127.121.246 via 192.168.1.1 dev eth0 proto static
192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.103 metric 1
edit: Output from "traceroute 8.8.8.8"
traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets
1 10.1.0.1 (10.1.0.1) 57.858 ms 57.848 ms 57.850 ms
2 174.127.120.1.static.midphase.com (174.127.120.1) 57.873 ms 58.141 ms 58.152 ms
3 ge-0-0-12.ar1.ord6.us.nlayer.net (69.31.110.85) 61.897 ms 61.913 ms 61.917 ms
4 ae5-60g.cr2.ord1.us.nlayer.net (69.31.110.253) 58.123 ms ae5-60g.cr1.ord1.us.nlayer.net (69.31.110.249) 58.264 ms 61.899 ms
5 ae1-30g.ar1.ord1.us.nlayer.net (69.31.111.134) 67.632 ms ae2-30g.ar1.ord1.us.nlayer.net (69.31.111.138) 67.634 ms 67.586 ms
6 TenGigE0-0-1-0.GW5.CHI13.ALTER.NET (63.84.100.185) 64.629 ms 56.640 ms 56.632 ms
7 0.xe-11-3-0.GW10.IAD8.ALTER.NET (152.63.35.237) 79.803 ms 80.161 ms 80.118 ms
8 google-gw.customer.alter.net (152.179.50.50) 81.249 ms 85.203 ms 85.715 ms
9 * 209.85.252.46 (209.85.252.46) 95.163 ms 209.85.252.80 (209.85.252.80) 85.975 ms
10 72.14.236.146 (72.14.236.146) 85.989 ms 86.221 ms 85.982 ms
11 72.14.235.12 (72.14.235.12) 93.830 ms 66.249.95.229 (66.249.95.229) 94.196 ms 66.249.95.231 (66.249.95.231) 93.752 ms
12 72.14.234.53 (72.14.234.53) 94.114 ms 72.14.234.55 (72.14.234.55) 90.566 ms 72.14.234.65 (72.14.234.65) 89.864 ms
13 * * *
14 google-public-dns-a.google.com (8.8.8.8) 89.826 ms 89.831 ms 90.489 ms
ip route show
.default...
) should probably not point to your VPN but to a router in the 192.168.1.0/24 network. If my suspicion is correct we will still have to find out what causes that.