Networking problem

You need a layer 3 switch (called a MLS - multi-layer-switch) that will do the router function and the switching. The static IP comes from your ISP.

You cannot use the same static IP in the router and some other tapped-off device. I assume that there is just one static IP available from the ISP.

You should configure the router to tap off the protocols / ports to the externally accessible network segment, usually called DMZ (de-militarized zone). The tapping-off is often called port forwarding.

accessible static IP. But adding the hub (tried 2 they already have) brea ks the XP stations, but not the OOMA (VoIP) phones.

maintain it.

We had dynamic IP before, but just added .248 or /29 static subnet. So, we should have 5 static IPs from the ISP. Yes, we can do port forwarding by r eplacing the dumb router with a Linux router, but trying to avoid placing t he Linux box in the critical path.

Even with just one uplink to the DSL modem and one downlink to the dumb rou ter. the XP stations stop working when adding the hub, However. OOMA VoIP still works. So, something is not getting pass the hub. Shouldn't a dumb hub just pass everything through?

Does this mean that you have a NAT router incapable of port forwarding?

There are small dedicated router/firewall boxes which will do it without explicit Linux (many of the network boxes contain embedded Linux without saying it aloud).

You should do traffic capture with and without the hub. My favourite tool is Wireshark.

ly accessible static IP. But adding the hub (tried 2 they already have) br eaks the XP stations, but not the OOMA (VoIP) phones.

o maintain it.

we should have 5 static IPs from the ISP. Yes, we can do port forwarding by replacing the dumb router with a Linux router, but trying to avoid placi ng the Linux box in the critical path.

router. the XP stations stop working when adding the hub, However. OOMA V oIP still works. So, something is not getting pass the hub. Shouldn't a d umb hub just pass everything through?

Probably not, at least not per port. It's a 4 port router with WiFi. One feeding a 24 ports switch and two feeding OOMA IP phones. We only need the last port as static IP. I have not look into the router setup. If we hav e to do major changes, might as well do it with a Linux router.

We would need to change the router upstream to static IP, in order to port forward to another externally accessible static IP. I was hopping that tap ping between the modem and router can avoid this change. It would make thi ngs simpler with or without the static IPs. The static IP could be tempora ry.

The reason for the static IP is an X-window display sink, until we can modi fy the software to run without X. We don't need to see the display, but it won't run without it. Several external virtual servers will be dumping th eir screen to this static IP, Unless we can find external virtual server w ith dummy display.

What makes you think that? Does your ISP actually *serve* that many IP's to you? E.g., I have a /24 network here -- but there's only one actual IP!

What is the XP host saying/not doing? Are you sure it isn't complaining about another host being on the network having *it's* IP?

Can the XP host ping anything (e.g., the OOMA boxes, configuration page inside the modem, etc.)?

Does it matter if you power up the XP host *before* the other (OOMA) hosts (i.e., give it time to claim the IP before it sees traffic to/from some *other* host having the same IP)

We asked, paid and confirmed with ATT DSL. They told us that we have 5 static IPs, .53 to .57 gw .58.

Yes, that does happen. But rebooting doesn't solve the problem. There could be problem with DHCP broadcast.

No, not really getting through DHCP.

I can look into these issues. But if they have to deal with such problems, this is probably not going to be the solution. We might have to take the static IP into another line or even another office.

from later descriptions it appears that your "modem" is actually a modem/router which explains the note "static IP"

mybe your second router deosn't do UPNP or avahi or whatever it is that XP needs to open a listening port on the public facing IP address

that opeion doesn't sound muh different to any other hardware you could put there.

OK.

Are you sure ATT is (still) providing the DHCP service? Can you watch the network traffic and *see* the broadcast (from the XP box) and "expected" reply from DHCP service?

Have you tried setting fixed IP's in the XP box et al. to verify that they can communicate when the IP issue is taken out of the mix?

So, the if you ipconfig /all on the XP host, you see a 169 (?) address?

I think an easier solution might be to just tell them (customer) to *set* the IP address of their hosts based on the *assigned* IP addresses from their provider. Take the DHCP client out of the picture entirely.

I don't think so, but will double check it next week.

But just adding a hub/switch between the modem and router should not change anything, right?

But it could be a "headed" machine, with a display we could access from the net.

I think so. I will setup a Linux box to check it. There are more tools to work with on Linux. Will decide later if that's going to be permanent.

There are more than 5 devices around. Pure static IP would not be possible.

You could try it to get additional data to evaluate/diagnose. Setting a fixed IP doesn't require any special tools (on most boxen).