No Network

Jeffrey F. Bloss jbloss at
Fri Jan 19 11:00:32 UTC 2007

Darren wrote:

> >> I have just removed iptables to no avail as well.
> >>
> >> Should you have any idea's that would be great, at this stage
> >> screenshots are a touch difficult.
> >>     
> >
> > If you have another PC on the network you can try starting ethereal
> > on that PC and ping to it, that way you will find out if your PC is
> > transmitting or not.
> >
> >   
> I didn't think of that before, I have just installed ethereal and no 
> traffic at all is listed as coming from (ubuntu box)
> I tried a tcpdump on eth0 and that made no mention of incoming ping
> request.
> Looking through dmesg it has
> 'device eth0 entered promiscuous mode'
> 'audit(series of numbers): dev=eth0 prom=256 old_prom=0
> auid=4294967295'
> 'device eth0 left promiscuous mode'
> 'audit(series of numbers): dev=eth0 prom=0 old_prom=256
> auid=4294967295'
> That appears to be repeated 3 or 4 times perhaps even more.

I don't have a whole lot to add, but that looks like normal Ethereal
activity. It's also a small indication of a working NIC. A quick
'ifconfig -a' could reveal a little more.

When you say you "removed iptables" what exactly do you mean? If you're
running a "white list" default DROP policy setup and flushed rules
with an 'iptables -F' or such it will leave you high and dry. With
netfilter truly "shut off" you should see something like this from a
'sudo iptables --list' ...

 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

If any of those ACCEPTs aren't ACCEPT it's a problem.

Some other off the cuff suggestions would be to redo your
Ethereal/tcpdump tests with something besides ping. Often times ICMP is
the first thing to go when something gets misconfigured. I'd use telnet
and try to connect to a port that should be open, but any port should
do. You're really looking for the attempt at this point. Don't forget
about tools like traceroute either, and if you have nmap available
anywhere that would be super.

Also... if you can you might want to try dropping in a LIveCD real
quick. If the problem disappears you can pretty much eliminate the
"bad hardware" thing and start concentrating on ferreting out and
fixing whatever it is that got buggered up in your server config. ;) 

     _?_      Outside of a dog, a book is a man's best friend.
    (o o)         Inside of a dog, it's too dark to read.
-oOO-(_)--OOo-------------------------------[ Groucho Marx ]--
    grok!              Registered Linux user #402208
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