So my neighbor and i wanted to somehow bridge our networks. We both have wired routers and he ran a cat5e cable from his 2nd desktop ethernet port to our router. We can now see his computer, and he can see our network. On his computer vista for reason reason defaulted to using our internet, but he can still see his network. He obviously wants to be able to use his internet, and wants us to be able to see his network. I'm not sure how windows handles two ips from both networks, but he seems to be able to access both networks. The question is if i can see his network through his desktop by bridging the two networks. I've done this with internet but not a whole network. Roommate said he could do it on linux but has no idea on windows. Any ideas?

3/9/2009 10:14:53 PM

Quote :

":carlface:"

3/9/2009 10:18:17 PM

I think we were able to bridge the internet and somehow that allowed me to see his network. He had to unbridge them to get his internet back though.

3/9/2009 10:20:25 PM

bridging is really not going to work here.

bridging would require that both of your networks use the same subnet. Then you run into the problem of two separate DHCP servers handing out addresses for the same subnet, and which router becomes the gateway to the Internet for what devices.

Ultimately, to do what you are trying to do will require a real, actual router, and not just a wireless AP with a switch that can do NAT and DHCP, which was what all consumer "routers" are.

3/9/2009 10:23:40 PM

That's what my roommate roughly said. He's the grad CPE. I'm just a stupid mechanical engineer. I knew about each DHCP having to hand out IP address and how that would conflict with each network, and having to tell which router, which devices used which gateway to the internet but for some reason Vista figured that out and it's working aside from the fact he's getting our internet.

His desktop to his router, plus his desktop to our router. Now we can both see each others networks, but he seems to be getting internet from us. Now if there's a way to tell his computer to use the gateway on his router instead of ours then we'd be set.

-Ok we're awesome. Figured it all out. We can see his network, and he can see ours. He's using his internet gateway, and we're using ours. Yay!

[Edited on March 9, 2009 at 10:51 PM. Reason : .]

3/9/2009 10:28:45 PM

route print is your friend here. Vista and most windows only keep one gateway by default for all networks. Youll have to manually set it, which I assume you did.

3/10/2009 9:40:26 AM

just put everybody on the same subnet and manually set the default gateway on each computer to be the router that you want to use for internet.

i think that'll work anyways.

3/10/2009 10:06:47 AM

yeah that will work actually.

i hate that i tend to overcomplicate things.

3/10/2009 10:35:04 AM

lol. i originally didn't think of that because i was trying to think of a way that was more secure and automatic.. so person A couldn't use person B's internet even if he wanted to.

bbbut, something tells me they don't really give a shit.

3/10/2009 10:44:41 AM

He says all he did was click "bridge connections" on his two Ethernet ports. Now it's just one big network, and they're using their internet gateway, and we're using ours. We double checked on all the computers, but it was as simple as that. Seems like Vista figured everything else out.

3/10/2009 12:47:04 PM

meh... i'd be interested to see exactly what it did

if you use the windows bridge, if both of your home gateways are on the same subnet and both handing out dhcp leases, you gon get raped have problems

3/10/2009 5:26:00 PM

this would be much simpler if you both had 2 nic's.. but manually specifying gateway is sufficient

[Edited on March 10, 2009 at 5:37 PM. Reason : .]

3/10/2009 5:36:46 PM

I guess you could all run hamachi.

https://secure.logmein.com/products/hamachi/vpn.asp?lang=en

3/10/2009 5:47:15 PM

we never manually specified the gateways. We did look at the network map though. I guess windows saw that one gateway was on one side of the bridge, and the other was on the other side, so it figured that's how each device would get internet. Everything seems to be working fine with no trouble at all. All we had to do was hook it up, and click bridge on the desktop connecting the two networks.

3/10/2009 5:54:32 PM

Quote :

"I guess windows saw that one gateway was on one side of the bridge"

IP does not work that way. I think you just coincidentally ended up that way. Windows can't "see" where one gateway is vs. another.

3/11/2009 8:12:26 AM

Vista will detect upnp devices and build a network map based on what it finds. Not sure if this extends to routers advertising their routes tho. So while its not going to find another gateway via tcp/ip, in theory if it sets its default gateway to the local router, it could find the "bridged" router's gateway address via upnp.

3/11/2009 9:54:41 AM

^^Well i brought up the network map under network settings and it clearly showed one gateway on one side of the bridge and the other gateway on the other side of the bridge. One network uses one gateway, and the other uses the other gateway by default, and we now have one big shared network. I don't know how it worked, all he did was bridge them through his desktop.

-But yeah the network map was an exact representation of our setup including switches, routers, and devices. Same as if i had drawn it.

[Edited on March 11, 2009 at 11:53 AM. Reason : .]

3/11/2009 11:52:31 AM

Quote :

"Not sure if this extends to routers advertising their routes tho."

i highly doubt a consumer grade router would employ RIP... especially considering most aren't really routers at all.

3/11/2009 12:00:44 PM

soooooo. how did this work without doing anything special?

3/11/2009 12:02:13 PM

luck.

3/11/2009 12:52:56 PM

Quote :

"i highly doubt a consumer grade router would employ RIP... especially considering most aren't really routers at all."

actually there are many consumer grade routers that can do RIP (its usually not enabled by default though) also Vista has rip support (not enabled by default either). But in the case of vista's network map we're talking upnp, which is not rip.

After some research it appears the network map is created from a combination of link layer topology discovery and upnp.

3/11/2009 12:56:54 PM

Ok we finally figured everything out so people weren't getting local/external IPs from both places randomly. We turned off our DHCP, and set static IPs to our computers. Now computers from across the hall won't be assigned an IP from us, but will default back to their IP.

Although we kinda have the advantage here because if someone gets wireless through our router, it'll still bypass that router (no DHCP) and get an IP from the router across the hall. It's kinda neat logging onto our wifi with our SSID, but seeing a local IP and internet from the other router.

Everything works perfect now. Mapped all our network drives for media and set up both HTPC's software to access both apartments on both 42's.

Something like this:


Router on the left has DHCP turned off.

[Edited on March 16, 2009 at 5:10 PM. Reason : .]

3/16/2009 5:08:23 PM

i'm sorry i have to ask.


Why ?

3/17/2009 2:04:04 PM

^joking i assume? A bunch of reasons. We can now play a lan game with both apartments. We both have large media libraries and htpcs on our tvs. This essentially doubles both our libraries. Why does anyone set up a network?

3/17/2009 2:07:54 PM

So for the gateways did you give each router a different ip on the same network and specify it manually for each comp?

3/17/2009 4:27:11 PM

Well right now one router has one set of ips with no DHCP, and the other has another set of ips. Any computer without a statically assigned ip will get an ip/gateway from the automatic DHCP router, while the others go to the router without DHCP.

Even though both networks have different ips (192.168.0.1 and 192.168.1.1) it still acts as one big network where we can share files, but in terms of gaming it seems the computers need to have the same network ip so later tonight we're setting both routers to use the 192.168.1.1 set. Our router will still have automatic DHCP turned off with a range of 50-100, while the other one will use DHCP to set automatic IPs under 50. So gaming will work no matter where you are on the network.

3/17/2009 4:44:01 PM

Thats interesting that file sharing works but other stuff doesnt. Can you ping a .0.X host from the .1.x network?

3/17/2009 5:04:50 PM

Yeah we can. Tried that. Windows seems to do fine combining the two networks for sharing, but i think for gaming you have to have the same network ip. I guess "lan" in gaming is defined as under the same network ip, but i'm not sure.

3/17/2009 5:08:18 PM

i'd guess that's probably due to netbios, IIRC, it's independent of IP and the way his network is setup, it's one big layer 2 broadcast domain.

3/17/2009 5:12:14 PM

My guess is its limiting the search for local servers to the local subnet. (or it could be really gay and use some non tcp/ip shit) I wonder if you left the router configs the way they were as far as dhcp goes, but set everythings subnet mask to 255.255.0.0 if it would work. Or am i totally off base?



[Edited on March 17, 2009 at 5:27 PM. Reason : 420 broadcast layer2 everyday]

3/17/2009 5:25:18 PM

I think that's what we had originally done, and it worked fine, but computers all over the place were getting either router ip and using that gateway at random. I guess once the computer floods the network with an ip request, whichever router that's faster will assign an ip with DHCP. That's about the extent of my knowledge though.

3/17/2009 6:20:09 PM

yea. The first router to respond wins. Its not toooo much of a problem if they distribute seperate ranges. The downside to both firing off dhcp is your gateway is going to be random. Your options to fix it are either static IPs or set up dhcp reservations for each device on the router you want it to use as its gateway. Both are about the same work to accomplish, but for future changes reservations are easier for embeded oses.

3/17/2009 6:23:56 PM

the dhcp routes to the ip address of the bridged standby gateway for the leased time slot, which explains the why vista gives you id match with 2 nic cards installed

3/17/2009 6:52:55 PM

Quote :

"the dhcp routes to the ip address of the bridged standby gateway"

what is this garbage you tried to post?

This sounds like some shit you see an actor who's playing a hacker say in a TV show or movie.

3/17/2009 7:43:31 PM

i read that and decided either i totally had lost him

or he was totally just typing random words

3/17/2009 8:12:26 PM

Go with one shared /24, and use your existing topology with both routers running dhcpd.

Unless I'm misunderstanding something, I only see a few possibilities allowing your 192.168.[01].x topology to work:

/23 mask on all devices
/24s exchanged between routers via routing protocols (or more likely statically set)

If neither of these are the case, I think you may have provided some inaccurate piece of information.

At any rate, given your requirements, neither of them are necessary.

[Edited on March 17, 2009 at 9:17 PM. Reason : reread]

3/17/2009 9:10:55 PM

^ no no no. if you have 2 routers running dhcp, and neither knows about the other, eg a linked/failover system, you will get ip conflicts up the wazhoo.

3/18/2009 8:24:22 AM

^no, you won't

Quote :

"Our router will still have automatic DHCP turned off with a range of 50-100, while the other one will use DHCP to set automatic IPs under 50"

3/18/2009 2:24:44 PM

DING DING

i mean, if you leave two el cheapo linksys routers set to their defaults then yea you'll have all kinds of IP conflicts

but not if it's setup like that ^

3/18/2009 2:26:40 PM

Actually one's a D-Link and one's a Linksys. So one is 192.168.0.1 and the other is 192.168.1.1 by default. So we never had ip conflicts to start with.

3/18/2009 4:12:33 PM

Understood. I was talking about your converged scenario, where both routers use the same /24.

3/18/2009 4:47:00 PM

there's also DHCP reservations... if you don't want to do the whole static IP setting manually.

3/18/2009 5:16:46 PM

Ok i didnt know i had to explain what i thought was an easy to understand statement

when the dhcp server posts a query for a ip matched database entry it has to secure a timeslot based on the clients end-point route registration, or EPRR, before a the bridge can query the other side of its network pair tree
which explains why vista, which uses 2-point ip matched query protocol, sees both networks and bridges them without a seperate span key provided per mod sec

3/19/2009 1:43:57 AM

Just get a 6509 and be done with it!

3/19/2009 11:35:01 PM

^^

I'm hoping you just picked out random words and put them into a post.

3/20/2009 10:17:18 PM

LLDP won't assign a gateway for you.

Furthermore, LLDP bombed a pcap of mine during a call because I forgot to disable it on server 2008 =P.

[Edited on March 21, 2009 at 12:54 AM. Reason : >.<]

3/21/2009 12:52:55 AM