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Interface can reach LAN fine, but not the internet

This is an Ubuntu 8.XX server, which runs in a VM and has worked fine till what seems as if it broke itself over the weekend.

it's IP address is configured properly.

/etc/resolv.conf:

Code:

nameserver 192.168.12.30

nameserver 65.39.152.237

route -n:

Code:

Kernel IP routing table

Destination    Gateway        Genmask        Flags Metric Ref    Use Iface

192.168.12.0    0.0.0.0        255.255.255.0  U    0      0        0 eth2

ifconfig:

Code:

eth2      Link encap:Ethernet  HWaddr 08:00:27:14:95:4a  

          inet addr:192.168.12.248  Bcast:192.168.12.255  Mask:255.255.255.0

          inet6 addr: fe80::a00:27ff:fe14:954a/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:50669 errors:0 dropped:0 overruns:0 frame:0

          TX packets:7793 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000 

          RX bytes:9435381 (8.9 MB)  TX bytes:4783941 (4.5 MB)

          Base address:0xc010 Memory:f0000000-f0020000 



lo        Link encap:Local Loopback  

          inet addr:127.0.0.1  Mask:255.0.0.0

          inet6 addr: ::1/128 Scope:Host

          UP LOOPBACK RUNNING  MTU:16436  Metric:1

          RX packets:231 errors:0 dropped:0 overruns:0 frame:0

          TX packets:231 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:0 

          RX bytes:27291 (26.6 KB)  TX bytes:27291 (26.6 KB)

Ping internal:

Code:

ping 192.168.12.90

PING 192.168.12.90 (192.168.12.90) 56(84) bytes of data.

64 bytes from 192.168.12.90: icmp_seq=1 ttl=64 time=0.419 ms

Ping external:

Code:

 ping www.google.ca

connect: Network is unreachable

I have it set up for static IP addressing. What is wrong? The gateway here is .253

Try:

Code:

route add default gw 192.168.12.253 eth2

If that doesn't work give the output of this command

Code:

ifconfig -a

I have done this.

Code:

route -n

Kernel IP routing table

Destination    Gateway        Genmask        Flags Metric Ref    Use Iface

192.168.12.0    0.0.0.0        255.255.255.0  U    0      0        0 eth3

0.0.0.0        192.168.12.153  0.0.0.0        UG    0      0        0 eth3

for whatever reason, when I tinkered with the virtualbox settings a little (I think I generated a new MAC address), it changed my interface to eth3. but it still works as it did before.

Still the same problem. Strangely enough, NSLOOKUP STILL WORKS. WTH!?

Code:

 nslookup www.google.ca

Server:                192.168.12.30

Address:        192.168.12.30#53



Non-authoritative answer:

www.google.ca        canonical name = www.google.com.

www.google.com        canonical name = www.l.google.com.

Name:        www.l.google.com

Address: 74.125.127.103

Name:        www.l.google.com

Address: 74.125.127.147

Name:        www.l.google.com

Address: 74.125.127.99

Name:        www.l.google.com

Address: 74.125.127.104

Code:

ping www.google.ca

PING www.l.google.com (74.125.127.147) 56(84) bytes of data.

From elandata.com (192.168.12.248) icmp_seq=2 Destination Host Unreachable

The answer was way beyond my troubleshooting thought process. This is the fix:

ifconfig eth3 mtu 1400

apparently I can't have an MTU of 1500 anymore :S

found the answer here:
http://ubuntuforums.org/showthread.php?t=432999

Quote:

Originally Posted by hawk__0 (Post 3507812)

That certainly is a bizarre problem, interesting though. MTU issues would be way down the list of initial items to check. Good catch!