Thank you everyone for the feedback. Although configuring the default
gateway on PC2 with its own IP address allowed me to ping from PC1 to PC2,
it caused some other problems in a part of the network that I omitted, so I
had to re-configure it back without a default gateway. Let me re-draw the
diagram to include the omitted part:
|-------------------Private Network-------------| -------------------Public
Network----------|
e0 e1 e0 e1 e0 e1
e0 e1
PC1-------router
A----------routerB---------PC2----------------routerC------------Internet
So, basically PC2 is a server with interfaces in a public and a private
network. Router A and router B connect an office to the hosting center via
a T1 line, that's why we need the router. Otherwise, there is no need for
the router on the private interface, since they can communicate via NetBIOS
names without any security concerns. What happened when I configured PC2
with it's own IP on the default gateway was that the public interface
stopped responding away (Windows 2000 server). When I configure the default
GW as routerB's address, the same thing happen but is sporadic and only
starts after a week or so. Weird!
As far as setting a default route, I don't think this will work on Windows
2000 unless it is acting as a router itself.
-Henrique
----- Original Message -----
From: "John Neiberger"
To:
Sent: Tuesday, May 14, 2002 3:04 AM
Subject: Re: ARP problems, anyone? [7:44108]
> I suppose this would depend on the behavior of PC2. Will it send ARP
> requests for all destinations if it doesn't have a default gateway
> configured? If so -- and you have Proxy ARP configured on Router B --
> then yes, Router B will respond with its own MAC address, allowing PC2
> to communicate with PC1.
>
> However, I don't recall that being normal behavior for a PC without a
> default gateway. I have heard, though, that if you use the IP address
> of the PC as its default gateway that some PCs will ARP for everything.
> It sounds like that's the sort of behavior you're looking for.
>
> To determine if Proxy ARP is enabled on Router B, use 'show ip int e1'.
> Somewhere in that output should be your answer.
>
> John
>
> >>> "Henrique Duarte" 5/13/02 3:50:37 PM >>>
> John,
> thanks for the feedback.
> So PC2 doesn't have a default gateway configured and will send a
> broadcast
> for the address of PC1. Since router B is on the same subnet and
> "knows"
> where PC1 is, shouldn't it respond as a proxy?
>
> -H
>
> ----- Original Message -----
> From: "John Neiberger"
> To:
> Sent: Monday, May 13, 2002 5:13 PM
> Subject: Re: ARP problems, anyone? [7:44108]
>
>
> > Unless you're bridging, ARP doesn't function here the way I _think_
> you
> > think it does.
> >
> > If PC2 receives an incoming ICMP echo request and it wants to
> generate
> > a response, it first compares the network portion of the destination
> > address to its own subnet. If you're not bridging they will be
> > different. In that case, PC2 will not send an ARP request for PC1,
> it
> > will simply forward the packet to the default gateway.
> >
> > Of course, at some point PC2 will send an ARP request to get the
> > hardware address of Router B, but it will never need to know the
> > hardware address of PC1.
> >
> > Now, if you're bridging then PC1 and PC2 should be on the same
> subnet
> > and neither would require a default gateway to speak to the other.
> >
> > HTH,
> > John
> >
> > >>> "Henrique Duarte" 5/13/02 2:50:43 PM >>>
> > OK Networking gurus. I hope you can help me with this easy one:
> >
> >
> >
> > e0 e1 e0 e1
> > PC1-------router A----------routerB---------PC2
> >
> >
> > PC1 can ping routerB (e1)
> > PC2 can ping routerA (e0)
> >
> > PC1 cannot ping PC2
> >
> >
> > PC2 has NO default gateway (and is not supposed to have one). I've
> > added a
> > static arp entry on PC2: PC1's IP address point to routerB e1's MAC
> > address. Why do I need the default gateway even though I already
> > configured
> > a static arp entry on PC2?
> >
> > Thanks in advance,
> >
> > -H
> [EMAIL PROTECTED]
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