Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

I have an issue with the internet connection in Ubuntu not working any longer.

I have two NIC's. Both static. One with a internet IP and one local. I can SSH into local fine, but the internet IP cannot be seen outside the network. I have 5 static internet IP's (only 1 assigned to this server) and the others work fine with the same configurations, so I know it's not the ISP. I can also ping the other internet IPs I have, but I can't ping out - say to google's 8.8.8.8.

netstat -rn
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
XX.49.84.232   0.0.0.0         255.255.255.248 U         0 0          0 eth1
172.24.98.0     0.0.0.0         255.255.255.0   U         0 0          0 eth0
0.0.0.0         XX.49.84.238   0.0.0.0         UG        0 0          0 eth1

/etc/network/interfaces file:
auto lo
iface lo inet loopback

auto eth0
allow-hotplug eth0
iface eth0 inet static
address 172.24.98.60
netmask 255.255.255.0

auto eth1
allow-hotplug eth1
iface eth1 inet static
address XX.49.84.237
gateway XX.49.84.238
netmask 255.255.255.248

Any ideas? Thank you so much!

share|improve this question

1 Answer 1

up vote 0 down vote accepted

Check route to 8.8.8.8:

$ ip ro get 8.8.8.8
8.8.8.8 via XX.49.84.238 dev eth0  src XX.49.84.237 
    cache  mtu 1500 advmss 1460 hoplimit 64

Then run tcpdump and ping 8.8.8.8:

# tcpdump -pni eth1                  (one console)
# ping 8.8.8.8                       (second console)

Copy output in question.

Also check ARP:

$ arp -a
XX.49.84.238 (XX.49.84.238) в xx:xx:xx:xx:xx:xx [ether] на eth1

And iptables rules:

# iptables -nv -L
share|improve this answer
    
ip ro get 8.8.8.8 8.8.8.8 via XX.49.84.238 dev eth1 src XX.49.84.237 cache mtu 1500 advmss 1460 hoplimit 64 –  KIT Feb 28 '11 at 16:10
    
Ok, then run tcpdump and ping simultaneity –  ooshro Feb 28 '11 at 16:11
    
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth1, link-type EN10MB (Ethernet), capture size 65535 bytes 10:12:21.522105 IP XX.49.84.237 > 8.8.8.8: ICMP echo request, id 4868, seq 1, length 64 --- times 5 ping 8.8.8.8 PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. ^C --- 8.8.8.8 ping statistics --- 5 packets transmitted, 0 received, 100% packet loss, time 4033ms –  KIT Feb 28 '11 at 16:13
    
arp -a does nothing –  KIT Feb 28 '11 at 16:15
    
sudo iptables -nv -L Chain INPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination –  KIT Feb 28 '11 at 16:16

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.