Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Bruce127]

Hello,

I hope this will be an easy question, but I haven't been able to figure out the answer.

How can I configure my DIR-655 router to use DHCP to give an address to a system that is not physically connected to the router (via one of the four ports) but physically connected elsewhere to the network. 

My house has wired connections throughout it and a patch panel in one of the bedrooms, but I want the router to stay out of the panel because of the wireless and I am trying to avoid having a separate router in the panel as this appears to be causing other problems.

Thanks, Bruce...

[davevt31]

A router can't hand an address to something its not connected too.  How is it going to know its there? 
If it is wireless it will get an address from the router, but if wired it won't unless connectd to it.

[EddieZ]

A connecting device will have to give out the IP. Either a PC (ICS), a switch or a router/modem. So the device that the device you're talking about is connected to (not being a router like you say) must be able to hand out an IP (DHCP). Otherwise there is no alternative.

[Bruce127]

I didn't do a good job of describing my problem.  Sorry.

I have an XBOX 360 in my living room and that network cable goes to the patch panel where I had it plugged into a hub.  Also plugged into that hub is the cable modem and a third cable that goes into my office where the D-Link router is located.  The D-Link and everything connected to it works fine, but the XBOX 360 can't get an IP address.  Any ideas on the problem?

When I replaced the hub (in the patch panel) with a different (Linksys) router then the XBOX 360 gets the IP address fine.  The D-Link router then gets it's IP from the Linksys, so they are chained.  But now the XBOX can't seems to get to the Windows PC connected to the D-Link router.  Should that work?

Thanks!  Bruce...

[EddieZ]

Perhaps you can add a diagram of your network structure. This is a non DIR655 issue and has more to do with generic networking principles. Your problem is the hub. And I guess the hub does not assign IP's and a router  (linksys) does.

[bananaman]

My money is on the way the hub is connected being the problem. What is the make and model of the hub?

Frankly I would ditch the hub in favor of a new switch.

Hubs have largely disappeared because switches have become so cheap. Most switches also auto-sense the connection type so you don't have to worry about crossover cables and dedicated uplink/downlink connection ports.

[funchords]

I'm afraid to answer this question because I don't think you'll believe me. 

You've been given a lot of confusing advice here.  Plus, you've probably confused yourself by playing around with the Linksys router.

How can I configure my DIR-655 router to use DHCP to give an address to a system that is not physically connected to the router (via one of the four ports) but physically connected elsewhere to the network. 

My house has wired connections throughout it and a patch panel in one of the bedrooms, but I want the router to stay out of the panel because of the wireless and I am trying to avoid having a separate router in the panel as this appears to be causing other problems.

This just works.  The only reason that the Xbox wouldn't grab an IP address from the DIR-655 is because it's probably trying to find whatever else was there before (it uses unicast for DHCP servers until the last minutes of a lease, then switches to broadcast -- the DIR-655 will handle it as soon as it switches to broadcast). 

Go back to start -- remove the Linksys router (you probably have it connected LAN-WAN which is segmenting your network anyway)*.  Go back to the hub. 

Remove power from the Xbox.  Hopefully when you restore power, it'll ignore any leases it had before and start broadcasting for a DHCP server.  If that doesn't work, then use the Xbox's controls to configure an IP address and then switch it back to DHCP.  That certainly should start it broadcasting for a server. 

Important: do not do any MAC address filtering on this network.

A router can't hand an address to something its not connected too.  How is it going to know its there? 
If it is wireless it will get an address from the router, but if wired it won't unless connectd to it.

I have 4 computers behind a wireless bridge, each one gets its own DHCP address from the DIR-655 without being directly connected to it.  No problemo.

A connecting device will have to give out the IP. Either a PC (ICS), a switch or a router/modem. So the device that the device you're talking about is connected to (not being a router like you say) must be able to hand out an IP (DHCP). Otherwise there is no alternative.

A DHCP server is not a feature of a switch or a router or a modem or even a gateway.  It's just an added-on thing.  So unless something about his set-up stops normal IP connectivity, this should just work. 

I didn't do a good job of describing my problem.  Sorry.

I have an XBOX 360 in my living room and that network cable goes to the patch panel where I had it plugged into a hub.  Also plugged into that hub is the cable modem and a third cable that goes into my office where the D-Link router is located.  The D-Link and everything connected to it works fine, but the XBOX 360 can't get an IP address.  Any ideas on the problem?

When I replaced the hub (in the patch panel) with a different (Linksys) router then the XBOX 360 gets the IP address fine.  The D-Link router then gets it's IP from the Linksys, so they are chained.  But now the XBOX can't seems to get to the Windows PC connected to the D-Link router.  Should that work?

Thanks!  Bruce...

Yes, you are double-natted in this configuration.  This is not how you want to be.  If you have a WAN port connected to your own LAN device, then you will have connectivity problems between those segments.  The only thing that should  be in a WAN port is your ISP's modem or ethernet tail. 

*If you want to use another home router somewhere in the middle of your network, first turn off its DHCP server and its UPNP server, then leave the router's WAN port empty and connect your cables to LAN ports only. That effectively turns that device into a switch.  If that device is wireless, it's probably also an access point. 

[EddieZ]

A DHCP server is not a feature of a switch or a router or a modem or even a gateway.  It's just an added-on thing.  So unless something about his set-up stops normal IP connectivity, this should just work. 

Funchords, could you please look up the definition of DHCP and the application of this feature in your textbooks?

Secondly, I would be very surprised if your suggestion (which is basically power on/off) actually worked. But anyway, being double NATted has no effect on getting an IP. Having two DHCP servers (and perhaps on the same subnet) can cause an issue. But the funny thing is (reading the guys text): when he has two routers installed with DHCP (1 extra instead of the hub) he does get an IP (because that makes the Xbox visible for the DHCP server). And with the hub in between he does not get an IP...

 

[funchords]

I know all about DHCP. Don't be an ass. 

I'm trying to help, but if I got something wrong, it's not permission to be a jerk.

being double NATted has no effect on getting an IP.

It has everything to do with getting the IP.  If he is double-natted, then the DHCP broadcast to 255.255.255.255 will only go to the client's segment (or sub-segment).  It will not be passed upstream and it will be filtered by any other NAT devices on that segment. 

If he's double natted, then he's probably got a segment that's 192.168.1.0/255.255.255.0 and one that's 192.168.0.0/255.255.255.0.  A DHCP broadcast from the 192.168.1.0 will not be heard on the 192.168.0.0 portion nor vice-versa. 

Now you said,

A connecting device will have to give out the IP. Either a PC (ICS), a switch or a router/modem. So the device that the device you're talking about is connected to (not being a router like you say) must be able to hand out an IP (DHCP). Otherwise there is no alternative.

That's simply not true.  In fact, if it's not a router, you would not want a DHCP server on that segment too. 

Routers separate different networks.  If it's not a router, then it's probably something from the family of hubs, bridges, or switches.  These attach items together onto the same IP subnet.   

Secondly, I would be very surprised if your suggestion (which is basically power on/off) actually worked.

What should have happened was that when he disconnected his Xbox ethernet cable, the Xbox's network card should have lost its IP address (due to autosensing) and when reconnected should have attempted to unicast recontact its issuing DHCP server directly (which would fail).  All of that probably happened.  It still had an unexpired lease.  We need to shake that invalid lease, which is probably what was keeping it from broadcasting for a new lease and this is why I made the suggestions that I made.  I don't like that theory myself, because it would be more robust if it broadcast for a lease when it couldn't reach its original server.  I'd like to think that Microsoft made the better choice, but since I don't know, I made a suggestion that is safe either way.

[EddieZ]

I know all about DHCP. Don't be an ass. 

I'm trying to help, but if I got something wrong, it's not permission to be a jerk.

And all are thankful. Apologies if my comments are to rude, but there are too many variables (subnets used etc.) you take for granted to come to your conclusions. Sometimes you do not need to go in that deep to solve an issue, the essence of my remarks from January 2 is absolutely true.

And fun of it all is that when he uses two routers (where you claim to be double NATted) instead of 1 router and a hub the Xbox is alive...

[Lycan]

Of course the HUB's not going to work, the modem can only assign 1 IP address, thats what the routers for. Put the router where the hub was and get a small switch, or even turn the Linksys router in to a switch AP. Then everything will work.
Simple.

[EddieZ]

Of course the HUB's not going to work, the modem can only assign 1 IP address, thats what the routers for. Put the router where the hub was and get a small switch, or even turn the Linksys router in to a switch AP. Then everything will work.
Simple.

As was my reply in 'Joe Average' speak.

[Bruce127]

Hello,

Thanks for everyone's feedback.  I've reconnected the switch (I incorrectly called it a hub) but the XBOX 360 (or any other device connected to it) still can't get an IP address from the D-Link router.

Devices connected directly to the back of the router get an IP okay.  Just not the ones connected to the switch.

Here is a link to my home network diagram. 
http://www.915jewell.com/HomeNetwork.pdf

(I was unable to upload to the forum due to the error that the upload directory was not writable.)

Thanks!  Bruce...

[EddieZ]

Thanks, this clarifies a lot.
From your drawing, the Xbox should get an IP from the modem or switch (what kind of switch is it anyway? managed or unmanaged?), not from the 655! The modem connects to the switch WAN port, as input signal. The Dir 655 is connected to a port and receives a signal which is distributed to the 'Office' PC's.In this case, the subnets that are used are most important. Which subnet is the modem on and which is the DIR on? Has the modem DHCP turned on or does the switch take care of that?

In short, this is not a DIR655 issue but a general networking issue...And yes, placing the Linksys instead of the switch will assign an IP to the Xbox and internet access....that's what routers do.

My suggestion would be to change the switch and DIR. That would be a good working config.

[Bruce127]

Thanks EddieZ.

The switch is a simple 5-port Netgear, so I guess you would call it unmanaged.

Shouldn't the broadcast request for the IP address be able to go through the switch and be heard by the 655?

I am using the 192.168.1.0/255.255.255.0 subnet on the DIR-655.  The DIR-655, has already gotten an address via DHCP from the cable modem.

I didn't want to put the DIR-655 in the closet for fear that the wireless range would be diminished as the cabinet has a metal door.  But perhaps it will be okay.

Given that this was not a DIR-655 issue - originally I thought something was stopping it from handing out an address - I appreciate the assistance that everyone has provided!

Thanks, Bruce...