Ubuntu 6 network problem

[Clint Tinsley]

> ----- Original Message -----
> From: "Vincent Trouilliez" <vincent.trouilliez at numericable.fr>
> To: ubuntu-users at lists.ubuntu.com
> Subject: Re: Ubuntu 6 network problem
> Date: Sat, 22 Jul 2006 12:57:26 +0200
> 
> 
> > Hello there: I've just installed Ubuntu on my hp laptop. The 
> > initial install was fine. However as soon as I connected to the 
> > internet, throught a b/band router it told me there were 128 
> > updates waiting. So I let it do all the updating. And then it 
> > asked for a restart and when I did that....no more internet. I've 
> > tried all the networking gui's and they say the NIC is active but 
> > it won't connect to anything. I can't ping anywhere except 
> > localhost either. Can someone offer some suggestions, please?
> 
> It happens to me as well, often when I reboot into Edgy to update 
> it then go back to Dapper.
> The Network GUI also always tell me that my NIC is active. What has 
> always worked for me so far, is to disable the NIC, then enable it 
> again, then make sure that the proper NIC is selected as default 
> gateway (often, no NIC is selected).

This is not correct.  You need to use the route command such as route -n to find out the gateway setting.
I verified this on my install of Dapper. My route command returns this:
desktop:~# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
172.30.0.0      0.0.0.0         255.255.255.0   U     0      0        0 eth0
0.0.0.0         172.30.0.65     0.0.0.0         UG    0      0        0 eth0
The gateway here is my router.
I put thise email out on my dist list for my user group and two of my members responded having the same problem, one ditched Dapper (not recommended) but the other replied the the update messed the DNS setting such that he could not get out to the internet.

I recommend you do a dig such as this:

desktop:~# dig www.ubuntu.com

; <<>> DiG 9.3.2 <<>> www.ubuntu.com
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7365
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 3

;; QUESTION SECTION:
;www.ubuntu.com.                        IN      A

;; ANSWER SECTION:
www.ubuntu.com.         401     IN      A       82.211.81.166

;; AUTHORITY SECTION:
ubuntu.com.             3057    IN      NS      ns.ubuntu.com.
ubuntu.com.             3057    IN      NS      ns0.blackcatnetworks.co.uk.
ubuntu.com.             3057    IN      NS      ns1.blackcatnetworks.co.uk.

;; ADDITIONAL SECTION:
ns.ubuntu.com.          80726   IN      A       82.211.81.173
ns0.blackcatnetworks.co.uk. 171132 IN   A       193.201.200.34
ns1.blackcatnetworks.co.uk. 171132 IN   A       69.55.225.40

;; Query time: 58 msec
;; SERVER: 205.171.3.65#53(205.171.3.65)
;; WHEN: Sat Jul 22 14:58:45 2006
;; MSG SIZE  rcvd: 171

The server listed at the bottom is the DNS server at my ISP.

You might also cat the resolv.conf for nameservers entries in /etc:
desktop:/etc# cat resolv.conf
search domain.actdsltmp
nameserver 172.30.0.65
nameserver 205.171.3.65

Clint