Internet over ethernet. Dns works, ping doesn't (Windows works, linux doesn't))

[badook]

Please help! I have a pc connected to the internet using an ethernet connection. Using ubuntu I am able to resolve domains using nslookup, but if I try to run "ping google.com" or "ping 74.125.39.104" it doesn't work.
I have used archlinux, mint and ubuntu live on two netbooks, all of them unsuccessfully. Windows, however, works just fine.
Please help me! Save me from using windows!!!

Here is some network info:

sudo ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:26:18:80:79:18  
          inet addr:10.20.6.180  Bcast:10.20.7.255  Mask:255.255.254.0
          inet6 addr: fe80::226:18ff:fe80:7918/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5751 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2397 errors:0 dropped:0 overruns:0 carrier:17
          collisions:0 txqueuelen:1000 
          RX bytes:659976 (659.9 KB)  TX bytes:253881 (253.8 KB)
          Interrupt:40

route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.20.6.0       0.0.0.0         255.255.254.0   U     1      0        0 eth0
169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 eth0
0.0.0.0         10.20.6.1       0.0.0.0         UG    0      0        0 eth0
0.0.0.0         10.20.6.1       0.0.0.0         UG    202    0        0 eth0

netstat -nr
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
10.20.6.0       0.0.0.0         255.255.254.0   U         0 0          0 eth0
169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 eth0
0.0.0.0         10.20.6.1       0.0.0.0         UG        0 0          0 eth0
0.0.0.0         10.20.6.1       0.0.0.0         UG        0 0          0 eth0

sudo iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

Tracepath is not working

sudo tracepath www.google.com
 1:  laptop.local                                          0.342ms pmtu 1500
 1:  no reply
 2:  no reply
 3:  no reply
 4:  no reply

Thanks in advance.

[badook]

executing the command "host google.com" gives the correct output (the list of ip and mail ip)
Running "wget http://www.google.com" gives the following output:

--2011-08-16 22:41:28-- google.com 
Resolving www.google.com... failed: Name or service not known. 
wget: unable to resolve host address 'www.google.com'

What can the reason be? I guess it's related to the problem with tracepath...

[Furball588]

I'm failing to see how you're believing DNS is working., when your last post leads me to believe it isn't.

What do you have in /etc/resolv.conf?

[badook]

I'm failing to see how you're believing DNS is working., when your last post leads me to believe it isn't.

What do you have in /etc/resolv.conf?

cat /etc/resolv.conf
# Generated by resolvconf 
search uni-mannheim.de 
nameserver 134.155.96.51 
nameserver 134.155.96.53

sudo cat /etc/host.conf
# The "order" line is only used by old versions of the C library.
order hosts,bind
multi on

sudo cat /etc/nsswitch.conf
# /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
# If you have the `glibc-doc-reference' and `info' packages installed, try:
# `info libc "Name Service Switch"' for information about this file.

passwd:         compat
group:          compat
shadow:         compat

hosts:          files mdns4_minimal [NOTFOUND=return] dns mdns4
networks:       files

protocols:      db files
services:       db files
ethers:         db files
rpc:            db files

netgroup:       nis

executing "nslookup google.com" gives me the correct list of addresses...

nslookup google.com
Server:		134.155.96.51
Address:	134.155.96.51#53

Non-authoritative answer:
Name:	google.com
Address: 74.125.39.104
Name:	google.com
Address: 74.125.39.105
Name:	google.com
Address: 74.125.39.106
Name:	google.com
Address: 74.125.39.147
Name:	google.com
Address: 74.125.39.99
Name:	google.com
Address: 74.125.39.103

Thank you for your time

[badook]

Here is the correct wget, somehow i made a mistake before

wget google.com
--2011-08-17 11:05:01--  http://google.com/
Resolving google.com... 74.125.39.99, 74.125.39.103, 74.125.39.104, ...
Connecting to google.com|74.125.39.99|:80...

I also noticed that while tracepath stops almost immediately dig goes further.

dig google.com

; <<>> DiG 9.7.3 <<>> google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2643
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 4, ADDITIONAL: 4

;; QUESTION SECTION:
;google.com.			IN	A

;; ANSWER SECTION:
google.com.		175	IN	A	74.125.39.103
google.com.		175	IN	A	74.125.39.104
google.com.		175	IN	A	74.125.39.105
google.com.		175	IN	A	74.125.39.106
google.com.		175	IN	A	74.125.39.147
google.com.		175	IN	A	74.125.39.99

;; AUTHORITY SECTION:
google.com.		104161	IN	NS	ns4.google.com.
google.com.		104161	IN	NS	ns3.google.com.
google.com.		104161	IN	NS	ns1.google.com.
google.com.		104161	IN	NS	ns2.google.com.

;; ADDITIONAL SECTION:
ns1.google.com.		277325	IN	A	216.239.32.10
ns2.google.com.		277325	IN	A	216.239.34.10
ns3.google.com.		277325	IN	A	216.239.36.10
ns4.google.com.		277325	IN	A	216.239.38.10

;; Query time: 2 msec
;; SERVER: 134.155.96.51#53(134.155.96.51)
;; WHEN: Wed Aug 17 11:06:14 2011
;; MSG SIZE  rcvd: 260

[Headboy100]

Hi Badook, I ma having a very similar problem to yours, so rather than starting a new thread, I will watch this one closely. Maybe by swapping info we can come up with a solution?

I have got to exactly the same point as you; dig google.com responds with the correct addresses, but wget stops at the connecting to google.com ... part.

I have a similar network setup; a Windows server and an Ubuntu server behind an ipCop firewall. Both were connecting to the internet a few days ago, now only the Windows server connects. The Ubuntu server connects locally to the Windows server, and vice versa, in fact I am connecting to the Ubuntu server remotely by VNCing in to the Windows server and then SSHing to the Ubuntu server from behind the firewall.

Because Windows is connecting to the Internet, I'm happy that the DSL modem and the firewall are working correctly. I don't have any special rules in ipCop applying only to the Ubuntu server, so I don't think that's the issue. I have disabled UFW in Ubuntu.

I have restarted the Ubuntu server. I have checked the arp caches on both machines, and they both point to the same mac address for the gateway (firewall).

Using mtr google.com, I get:

1: ipcop.localdomain
2: ???

I am assuming this means that Ubuntu is finding the firewall okay, but can't get any further.

If I make any progress, I will post here.

Regards,
Nick

[Headboy100]

Well, I solved my problem at least. I had both eth0 and eth1 up, and both had a gateway setting of the firewall. By removing the gateway setting for eth1, everything works again. (I need to keep eth1 enabled for a virtual server that needs a static ip address)

I don't know if this will help Badook or not.

[Iowan]

[SOLVED] ?