[K12OSN] server not forwarding packets for Windows clients

[Les Mikesell]

On Mon, 2006-01-30 at 14:54, Petre Scheie wrote:
> > 
> > But I thought this should be enabled in a default k12ltsp install.
> > 
> I think it is.  I built the server in my basement and successfully tested it with some 
> thin clients; but I didn't try any Windows clients.  But I think something else must be 
> going on because when I logged in at the console, while I could ping things like google 
> & yahoo, firefox had trouble with them: first it wouldn't load any thing, then after 
> shutting it down and restarting it, it could bring up a google page, but not yahoo; shut 
> it down and restart it again and google and yahoo are accessible, but not others.  I ran 
> 'host' on those & other websites and while I'd get an answer, I also got an error about 
> the parser  receiving misformatted data.  In /etc/resolv.conf, there were two resolver 
> addresses: the Linksys router, and the DNS server of the ISP.  I commented out the 
> Linksys address, and then 'host' didn't get any more errors, but users still couldn't 
> connect to the internet.  Here's how the network is layed out; it doesn't look like 
> anything special to me.
> 
> Internet-->ActionTec DSL bridge-->LinkSys Router w/wireless--> \
> 
> -->8-port switch-->K12ltsp-->24-port switch-->clients
> 
> I suppose I could check for bad packets and cables.  Any other ideas of things to look for?

Try to separate the DNS issues from packet forwarding/NAT.  The
entries in /etc/resolv.conf are for DNS client lookups happening
on the server itself.   The server also runs a DNS server that
is used by the machines 'behind' it - that is, the ones that
obtain their settings via DHCP.  You should be able to do
a 'dig @localhost' on the server to see if the dns server
is working and an 'nslookup some_internet_address' on a windows
box behind it if so.  If that is OK, then move on to the
nat/forwarding.   On the server:
iptables --list -t nat
should show
Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination
MASQUERADE  all  --  anywhere             anywhere

-- 
  Les Mikesell
   les at futuresource.com