dhcp does not work with SiS SiS900 PCI Fast Ethernet (rev 91)

[Rick Stevens]

On Tue, 2007-05-08 at 09:56 -0700, Antonio Olivares wrote:
> --- "Mikkel L. Ellertson" <mikkel at infinity-ltd.com>
> wrote:
> 
> > Antonio Olivares wrote:
> > > --- "Mikkel L. Ellertson"
> > <mikkel at infinity-ltd.com>
> > > wrote:
> > > 
> > >>
> > >> Now, as far as fixing the real problem, we need
> > more
> > >> information
> > >> about your network. Do other computers on the
> > >> network work using
> > >> DHCP? 
> > > 
> > > Yes computers on the network are configured using
> > > dhcp, each computer with a MAC address in the
> > network
> > > gets its ip automatically and everything should
> > work,
> > > but mine does not. 
> > > 
> > Is the DHCP server configured to only respond to
> > registered MAC
> > addresses?? If so, did you register yours?
> 
> Yes it is.  The dhcp server is configured by its mac
> address.  Yes it is registered.  
> 
> > > 
> > >> Are you running a firewall on your
> > >> Linux system, and if
> > >> so, is it configured to allow DHCP?
> > > 
> > > I think the normal firewall that comes with Fedora
> > is
> > > running, but How do I know if it does allow/not
> > allow
> > > DHCP to work?
> > > 
> > The standard firewall should allow DHCP to work
> > without problems. An
> > easy way to check is to turn off the firewall, and
> > see if that
> > helps. You can also check the logs to see if the
> > firewall is
> > blocking DHCP, or other error messages when you try
> > to use DHCP to
> > configure the interface. The log files should always
> > be one fo the
> > first places to look when you have hardware/network
> > problems.
> > 
> > Mikkel
> > -- 
> > 
> >   Do not meddle in the affairs of dragons,
> > for thou art crunchy and taste good with Ketchup!
> > 
> > -- 
> > fedora-list mailing list
> > fedora-list at redhat.com
> > To unsubscribe:
> > https://www.redhat.com/mailman/listinfo/fedora-list
> > 
> 
> Which log file(s) should I look at?  
> # dmesg
> # tail -f /var/log/messages

Have you tried running "dhclient eth0" from the command line (assuming
eth0 is your wireless card) and watched its output?  That may give you
some better ideas as to what's going on.  You should also have a look
at the DHCP server's logs.

My guess is that you really don't have the MAC address of the machine
registered with the DHCP server (it's easy to make a mistake with six
hex octets) or that your iptables is blocking it.  DHCP uses UDP port 68
(sometimes TCP port 68), so make sure iptables isn't blocking it
(iptables is started before the network interfaces are brought up).  If
you need some rules for iptables to allow DHCP, here they are:

	-A INPUT -p tcp -m tcp --dport 68 -j ACCEPT
	-A INPUT -p udp -m udp --dport 68 -j ACCEPT

Stick them somewhere appropriate in your /etc/sysconfig/iptables file
and restart iptables.
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- Rick Stevens, Principal Engineer             rstevens at internap.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-           grep me no patterns and I'll tell you no lines           -
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