Re: DHCP Strangest Problem I ever Seen in my life

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Date: Thu, 25 Mar 2004 16:04:43 -0600

> spanning tree is setup only on the trunk ports. I debuged the switches and
I
> don't find anything unnusual, i used ethereal and etherpeek to snif the
> network and the clients don't send a single packet to the dhcp, one of the
> test I made is to isolate one of my DC in a hub and put two of the
> workstation with the problem on it, and the problem persist. I really
don't
> know what else to do.

Did you actually sniff FROM the workstation to see if it is
transmitting the DHCP discover etc?

If not, you have (obviously) a pure workstation problem as long as
the wire is plugged in and active -- put them on a cheap multiport
repeater hub with NEW drop cables and check this.

-- 
Herb Martin
"Emiliano G. Estevez" <eestevez@sistran.com.ar> wrote in message
news:eP1cQfpEEHA.2628@TK2MSFTNGP11.phx.gbl...
> All my switches are Cisco Systems and one of them wich is the core is a
> Catalyst 3550 all the ports in all the switches are set to full duplex and
> 100 MB port fast (wich means that doesn't check for spanning tree states)
>
> Best regards.
>
> "Herb Martin" <news@LearnQuick.com> wrote in message
> news:OLHdMXpEEHA.624@TK2MSFTNGP10.phx.gbl...
> > > I have three domain controllers two are in a site and the other is in
> > > another site, on the three domain controllers I have setup DHCP, wins
> and
> > > DNS, they all have the latest hot fixes, services packs, and the three
> > DHCP
> > > servers are authorized in AD, the problem I have is that suddenly the
> > > computers in my network that have to renew his IP address don't get
one,
> > and
> > > the worst thing is that when the computer is restarted with the patch
> cord
> > > plugged the system gets a lot of time to logon and once the system is
on
> > > line and we check for the IP address the IP address is 0.0.0.0 this is
> > weird
> > > because the system in the case that a DHCP server is not found and can
> > > contact the default gateway will renew his IP address and if the
default
> > > gateway is no found the system will get an APIPA well that doesn't
work,
> > if
> >
> > Yes, that should happen -- unless the machines have disabled APIPA
> > through the registry or a policy setting.
> >
> > General method when you have a problem "this weird" -- put a network
> > monitor (NetMon, Ethereal, WinDump, Sniffer) on the line and watch
> > the exchange.
> >
> > DHCP traffic is easy to filter and isolate.
> >
> > > we set the IP address of the workstation to a fixed IP address the
> problem
> > > is gone, but this is no viable because I have almost 300 workstations,
> > other
> > > weird thing is that if I unplugged the patch cord the computers boots
up
> > > normally, I logon to the workstation with cached credentials and then
I
> > > plugged the patch cord, go to the cmd and type ipconfig /renew and I
get
> > an
> > > IP address.
> >
> > My guess would be that you have some sort of "hub/switch" hardware
> > problem where the port is being shutdown, thus convincing the machines
> > that they are not plugged into a cable (link detect enabled.)
> >
> > > I put a sniffer on my switchs and the network cards when they are set
> for
> > > DHCP when they are restarting doesn't send any dhcpinform packets in
> fact
> >
> > That would probably be DHCPDiscover (inform is mostly used between
> > DHCP servers for things like "authorization" info.)
> >
> > Expect this:
> >     DHCPDiscover (from client)
> >     DHCPOffer (from server)
> >     DHCPRequest (from client)
> >     DHCPAck or NACK (from client)
> >
> > > the doesn't send any packets at all, If I disable the dhcp service on
my
> > DC
> > > and setup my catalyst 3550 as a dhcp server the problem is exactly the
> > same
> > > so I figured out that the dhcp service from MS is not involved but
maybe
> I
> > > am missing something, I am very frustrated about this and there is a
> week
> > > now that I can't solve this problem, please I need a hand on this.
> >
> > You have pretty much isolated it to the CLIENTS or net hardware.
> > Either the clients are not making the request, or it isn't getting
> through.
> >
> > What happens if you monitor FROM the client (to see if they think they
> > are sending requests.)?
> >
> > IF the clients are not sending, then the question arises as to whether
> > the switch is confusing them or turning of their port so they think they
> > are disconnected OR if they are just in error on their own.
> >
> > I would tend to suspect the former, since most people in the world
> > are not having such problems with Windows clients.
> >
> > Are you familiar with "link detect" and how a switch might interact
> > with that setting to confuse the client or to just block the request
even
> > if the client made it?
> >
> >
> >
> >
> >
> > -- 
> > Herb Martin
> > "Emiliano G. Estevez" <eestevez@sistran.com.ar> wrote in message
> > news:e$L8G6oEEHA.1600@tk2msftngp13.phx.gbl...
> > > Hi,
> > >
> > >
> > >
> > >
> > >
> > >
> > > Best Regards.
> > >
> > >
> >
> >
>
>

• Previous message: Jetro: "Re: DHCP Strangest Problem I ever Seen in my life"
• In reply to: Emiliano G. Estevez: "Re: DHCP Strangest Problem I ever Seen in my life"
• Next in thread: J.C. Hornbeck [MSFT]: "Re: DHCP Strangest Problem I ever Seen in my life"
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