Network Bridge Strangeness
Discussion
Can someone please help me before i throw my laptop and Xbox 360 out of the nearest window!
Ok, some background, got a vaio laptop which connects to the wireless network at home using a cheap as chips PCMCIA wireless card. Recently picked up an Xbox 360 and decided to hook it up to xbox live and to share music and pictures using Windows media connect.
Figured the best way to do it would be to hook the xbox up to my laptop using an ethernet cable and then create a network bridge between the LAN and Wireless connection. Before creating a bridge i plug the ethernet cable in, windows tries to acquire an ip address for about a minute and the announces that it has limited or no connectivity. It has using Auto Private Adressing giving it a 169.xx.xx.xx address. Even with this "limited connectivity" i tested Windows media connect and it would happily share music and pictures with the box. Now i create the bridge and after windows spends a minute sorting itself out it tells me that wireless, lan and the bridge itself are all happily connected.......except i cant connect to the internet......hmmm....
The network bridge has an ip address, but its a 169.xx.xx.xx one (not sure if An automatic address is a problem with the bridge) but the Ip address of the wireless and lan are blank. The basic problem seems to be that the lan cannot seem to get a DHCP assigned address. Did some research on the net and after lots of messing about using ipconfig and netsh i have given up! I tried the same setup using my girlfriends thinkpad and it worked perfectly first time! GRRRRRR
Any Ideas what i might be doing wrong? Any help much appreciated.
Ok, some background, got a vaio laptop which connects to the wireless network at home using a cheap as chips PCMCIA wireless card. Recently picked up an Xbox 360 and decided to hook it up to xbox live and to share music and pictures using Windows media connect.
Figured the best way to do it would be to hook the xbox up to my laptop using an ethernet cable and then create a network bridge between the LAN and Wireless connection. Before creating a bridge i plug the ethernet cable in, windows tries to acquire an ip address for about a minute and the announces that it has limited or no connectivity. It has using Auto Private Adressing giving it a 169.xx.xx.xx address. Even with this "limited connectivity" i tested Windows media connect and it would happily share music and pictures with the box. Now i create the bridge and after windows spends a minute sorting itself out it tells me that wireless, lan and the bridge itself are all happily connected.......except i cant connect to the internet......hmmm....
The network bridge has an ip address, but its a 169.xx.xx.xx one (not sure if An automatic address is a problem with the bridge) but the Ip address of the wireless and lan are blank. The basic problem seems to be that the lan cannot seem to get a DHCP assigned address. Did some research on the net and after lots of messing about using ipconfig and netsh i have given up! I tried the same setup using my girlfriends thinkpad and it worked perfectly first time! GRRRRRR
Any Ideas what i might be doing wrong? Any help much appreciated.
ok - I know nothing of windows (don't really care...) but this is down to what you mean by a network bridge......
Basically a bridge is an old fashioned way of carrying layer 2 traffic across a layer 3 device (without having to route). So logically what you are trying to do is connect your laptop to the wireless network, it will only talk to the internet if it has a Layer 3 IP address. If your wireless interface is showing 169.xxxx this means that it has failed to get a valid IP address and will not be able to reach the internet.
Seperately you have connected the Xbox to the laptop using a layer 2 connection, and I guess from what you say they are talking. However, the only way this can work is if your Xbox gets an IP address, and your laptop acts as a layer 2 device (bridge), so logically the Xbox will be in the same Layer 3 subnet as the Broadband router that is attached to your wireless network (the IP gateway and DHCP server...).
If your laptop gets an IP address from the wireless network (DHCP) then you would need to make your laptop a ROUTER, so that means give your laptop LAN interface an IP address, and give one to the Xbox (or make your laptop a DHCP server to give an address to the Xbox) - the only other way to do it is by creating a DHCP scope for your LAN on the existing DHCP server, and getting your laptop to forward bootp(dhcp) to the xbox - which I bet you can't do.....
Not sure why your gf's works, her laptop'll be set up differently, but it isn't just down to the type of laptop as this is just standards based stuff.....
to summarise...
10.0.0.2 10.0.0.1
| |
| |
XBOX--------------LAPTOP-------------------ADSL ROUTER/DHCP SERVER---------INTERNET
| | |
| | Also needs a route for 10.0.0.0
192.168.0.2 192.168.0.1 with a gateway of 192.168.0.2
or:
192.168.0.2
|
XBOX--------------LAPTOP-------------------ADSL ROUTER/DHCP SERVER---------INTERNET
| |
| |
Bridge 192.168.0.1
Basically a bridge is an old fashioned way of carrying layer 2 traffic across a layer 3 device (without having to route). So logically what you are trying to do is connect your laptop to the wireless network, it will only talk to the internet if it has a Layer 3 IP address. If your wireless interface is showing 169.xxxx this means that it has failed to get a valid IP address and will not be able to reach the internet.
Seperately you have connected the Xbox to the laptop using a layer 2 connection, and I guess from what you say they are talking. However, the only way this can work is if your Xbox gets an IP address, and your laptop acts as a layer 2 device (bridge), so logically the Xbox will be in the same Layer 3 subnet as the Broadband router that is attached to your wireless network (the IP gateway and DHCP server...).
If your laptop gets an IP address from the wireless network (DHCP) then you would need to make your laptop a ROUTER, so that means give your laptop LAN interface an IP address, and give one to the Xbox (or make your laptop a DHCP server to give an address to the Xbox) - the only other way to do it is by creating a DHCP scope for your LAN on the existing DHCP server, and getting your laptop to forward bootp(dhcp) to the xbox - which I bet you can't do.....
Not sure why your gf's works, her laptop'll be set up differently, but it isn't just down to the type of laptop as this is just standards based stuff.....
to summarise...
10.0.0.2 10.0.0.1
| |
| |
XBOX--------------LAPTOP-------------------ADSL ROUTER/DHCP SERVER---------INTERNET
| | |
| | Also needs a route for 10.0.0.0
192.168.0.2 192.168.0.1 with a gateway of 192.168.0.2
or:
192.168.0.2
|
XBOX--------------LAPTOP-------------------ADSL ROUTER/DHCP SERVER---------INTERNET
| |
| |
Bridge 192.168.0.1
Edited by guydw on Tuesday 22 August 11:47
The formatting didn't work on the diagram....
so th explain, the xbox is 10.0.0.2, the laptop LAN side is 10.0.0.1, Laptop wireless side is 192.168.0.2 and wireless router/adsl (whatever) is 192.168.0.1.
These addresses are examples......
The wireless/adsl router needs a route to reach the 10.0.0.0 network which goes via the laptop. The laptop doesn't need a route as it is directly connected to both networks and has the wireless router as it's default gateway, the xbox needs a default gateway of the laptop LAN interface (so it knows to send all traffic that way).
You can't have both laptop and Xbox getting DHCP addresses from the adsl router and being on the same network without using a hub or switch as the laptop can't be a bridge and an IP host at the same time (unless Microsoft have somehow cludged this, which is unlikely and very nasty... anyone know better?)
so th explain, the xbox is 10.0.0.2, the laptop LAN side is 10.0.0.1, Laptop wireless side is 192.168.0.2 and wireless router/adsl (whatever) is 192.168.0.1.
These addresses are examples......
The wireless/adsl router needs a route to reach the 10.0.0.0 network which goes via the laptop. The laptop doesn't need a route as it is directly connected to both networks and has the wireless router as it's default gateway, the xbox needs a default gateway of the laptop LAN interface (so it knows to send all traffic that way).
You can't have both laptop and Xbox getting DHCP addresses from the adsl router and being on the same network without using a hub or switch as the laptop can't be a bridge and an IP host at the same time (unless Microsoft have somehow cludged this, which is unlikely and very nasty... anyone know better?)
brain ache...........
I understand what you are saying, the laptop and xbox can communicate with any address they want, when the bridge is active. but the wireless needs a 192.xx.xx.xx address from the router. Which, when not bridged, it gets fine. The problem arises when bridged, the wireless says it is connected to the router and good signal etc but when i load up firefox i cant get any sites up.
so, rereading again, i can specify manual ip addresses and subnet mask for the laptop and xbox and then specify the default gateway for the laptop to xbox connection to be the default gateway of the wireless connection?
I understand what you are saying, the laptop and xbox can communicate with any address they want, when the bridge is active. but the wireless needs a 192.xx.xx.xx address from the router. Which, when not bridged, it gets fine. The problem arises when bridged, the wireless says it is connected to the router and good signal etc but when i load up firefox i cant get any sites up.
so, rereading again, i can specify manual ip addresses and subnet mask for the laptop and xbox and then specify the default gateway for the laptop to xbox connection to be the default gateway of the wireless connection?
Edited by mallone on Tuesday 22 August 12:59
um... the default gateway has to be on the same network as the host, and is the route that would be taken to reach the internet... to make your laptop a router you need to turn on IP forwarding, you also need to add a route to your adsl router to reach the far network (which is the network between the laptop and xbox)- you should be able to figure this out from the gui.
Quick routing overview...
a host sends a packet onto its local network, if it is a layer 2 packet (broadcast) every other device physically attached to that local network will see that packet and reply. If it is a layer 3 packet (i.e. a packet sent to a specific IP address - like ping) it will also be seen by other hosts on the same network (that have IP addresses in the same range). If you ping an IP address in a different network (like the internet) you need to connect to that other network using a router.
A router is a device that has one interface in your network, and another interface in another network. It will not forward layer 2 packets, only packets bound for an IP address. The router has two options, it either knows about a network because it has an interface in that network (is directly connected), or it knows the way via another router (has a route configured).
So....
10.0.0.0--RouterA----20.0.0.0--RouterB----30.0.0.0
Router A has interface 10.0.0.1 and interface 20.0.0.2
Router B has interface 20.0.0.1 and interface 30.0.0.1
PC-1 with 10.0.0.10 wants to reach a PC-2 with 30.0.0.10
PC-1 doesn't know where 30.0.0.0 is, but has a default gateway of 10.0.0.1, so sends everything that doesn't start with 10.0.0.x to that gateway, which is Router A.
Router A is directly connected to 10.0.0.0 and 20.0.0.0, so knows about these with no extra configuration. It does not know about 30.0.0.0, so you have to configure a route that says 30.0.0.0 can be reached by going to 20.0.0.1 (Router B).
The packet reaches Router B, this router knows about 20.0.0.0 and 30.0.0.0 - it is directly connected. So the packet bound for 30.0.0.10 is delivered correctly.
But, how does it get back ? The return packet is for 10.0.0.10, which Router B does not know about, so there needs to be a route on Router B telling it to reach 10.0.0.0 via 20.0.0.2 (Router A).
This can go on for as many "hops" as you like, so:
10.0.0.0--RouterA----20.0.0.0--RouterB----30.0.0.0---RouterC---40.0.0.0
to reach 40.0.0.0 Router A needs to route via Router B (but doesn't need to know about 30.0.0.0) and Router B needs a route via Router C. Router C needs a route back via Router B, which in turn needs a route back via Router A.
Quick routing overview...
a host sends a packet onto its local network, if it is a layer 2 packet (broadcast) every other device physically attached to that local network will see that packet and reply. If it is a layer 3 packet (i.e. a packet sent to a specific IP address - like ping) it will also be seen by other hosts on the same network (that have IP addresses in the same range). If you ping an IP address in a different network (like the internet) you need to connect to that other network using a router.
A router is a device that has one interface in your network, and another interface in another network. It will not forward layer 2 packets, only packets bound for an IP address. The router has two options, it either knows about a network because it has an interface in that network (is directly connected), or it knows the way via another router (has a route configured).
So....
10.0.0.0--RouterA----20.0.0.0--RouterB----30.0.0.0
Router A has interface 10.0.0.1 and interface 20.0.0.2
Router B has interface 20.0.0.1 and interface 30.0.0.1
PC-1 with 10.0.0.10 wants to reach a PC-2 with 30.0.0.10
PC-1 doesn't know where 30.0.0.0 is, but has a default gateway of 10.0.0.1, so sends everything that doesn't start with 10.0.0.x to that gateway, which is Router A.
Router A is directly connected to 10.0.0.0 and 20.0.0.0, so knows about these with no extra configuration. It does not know about 30.0.0.0, so you have to configure a route that says 30.0.0.0 can be reached by going to 20.0.0.1 (Router B).
The packet reaches Router B, this router knows about 20.0.0.0 and 30.0.0.0 - it is directly connected. So the packet bound for 30.0.0.10 is delivered correctly.
But, how does it get back ? The return packet is for 10.0.0.10, which Router B does not know about, so there needs to be a route on Router B telling it to reach 10.0.0.0 via 20.0.0.2 (Router A).
This can go on for as many "hops" as you like, so:
10.0.0.0--RouterA----20.0.0.0--RouterB----30.0.0.0---RouterC---40.0.0.0
to reach 40.0.0.0 Router A needs to route via Router B (but doesn't need to know about 30.0.0.0) and Router B needs a route via Router C. Router C needs a route back via Router B, which in turn needs a route back via Router A.
i know its all a bit complex, and truth be told i could just connect straight to the router with a very long cable, but i still dont understand how it works on one laptop but not on the other. determined to at least try before spending money.
Plotloss, i tried disabling firewalls, didnt have any effect.
The situation now, after more fiddling is that the wireless, lan and xbox are all on the same 255.255.255.0 subnet. On that subnet the wireless has an ip address assigned by dhcp from the router, the laptop has an ip of 169.254.24.1 the xbox has 169.254.24.2
The laptop lan has a default gateway of the wireless routers IP, the xbox has a default gateway of the laptops ip.
With this setup the xbox reports a successfull connection to the network and the ip address is confirmed but then says it cant find the DNS servers. Any ideas as to what to fill in the xbox's DNS servers with?
Plotloss, i tried disabling firewalls, didnt have any effect.
The situation now, after more fiddling is that the wireless, lan and xbox are all on the same 255.255.255.0 subnet. On that subnet the wireless has an ip address assigned by dhcp from the router, the laptop has an ip of 169.254.24.1 the xbox has 169.254.24.2
The laptop lan has a default gateway of the wireless routers IP, the xbox has a default gateway of the laptops ip.
With this setup the xbox reports a successfull connection to the network and the ip address is confirmed but then says it cant find the DNS servers. Any ideas as to what to fill in the xbox's DNS servers with?
mallone said:
Routers ip didnt work as DNS server. The bridge looks like a better idea. Too annoyed with it to keep trying.
The cable was the one that comes with the xbox. I heard about the whole straight through/crossover problem but i assumed if it worked in one setup it should work in another.
Correct, unless one card can autonegotiate MDI/X and the other can't. The fact that you got an IP address from DHCP eliminates the cable though.The cable was the one that comes with the xbox. I heard about the whole straight through/crossover problem but i assumed if it worked in one setup it should work in another.
Read my earlier post.... 169.x.x.x is not a valid IP address, it is a default when the device can't get a DHCP address. If you have these devices all daisy chained together then they can't all be on the same network, they need a shared network device such as a hub or switch.
I don't know why the other laptop is working, but my guess is that the laptop doesn't have and IP address, it is acting as a layer 2 bridge to allow the xbox to talk to the adsl router. To clarify, can you explain what you mean when you say wireless - do you mena the wireless/ adsl router ?
I don't know why the other laptop is working, but my guess is that the laptop doesn't have and IP address, it is acting as a layer 2 bridge to allow the xbox to talk to the adsl router. To clarify, can you explain what you mean when you say wireless - do you mena the wireless/ adsl router ?
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