[Bridge] Re: bridge + tap?

Wayback MachineAbout this captureCOLLECTED BY Organization: Alexa Crawls Starting in 1996, Alexa Internet has been donating their crawl data to the Internet Archive. Flowing in every day, these data are added to the Wayback Machine after an embargo period. Collection: Alexa Crawls DE Crawl data donated by Alexa Internet. This data is currently not publicly accessible TIMESTAMPSloadingLennert Buytenhekbuytenh@gnu.org
Tue, 4 Apr 2000 23:58:15 +0200 (MEST)On Thu, 30 Mar 2000, PinkFreud wrote:> Hi, Lennert. Thought you might like to know – your bridge config utility> seems to work on an Alpha (Multia, aka UDB).Yay! Does the kernel code work as well?> That was the good news – the bad is that I need assistance with tap. :)That should be fun! It’s been a while since I last looked at it.> Basically, I noticed in your FAQ that you managed to use tap0 to let your> laptop be seen on the network. I’m trying to acheive the same result, but> without much success – although I think this can be attributed to the fact> that I don’t have a clue as to how to use tap. The documentation on> ethertap is vague, at best, and there doesn’t seem to be much by way of> documentation on your tap utility as of yet. :)My laptop has a nic now, so I don’t use that hack anymore.The ethertap idea is actually very clean: everything sent out on tap iswritten to listeners on /dev/tap, and everything written to /dev/tapis ‘received’ on tap.tap isn’t well-documented, I know. Feel like writing a howto after thisexplanation? :-)> Here’s my situation:>> I have a small ethernet network, and an even smaller wireless network> running here. My laptop (192.168.1.13) is using my Multia (bridge,> 192.168.1.7) to get out to the rest of my network (192.168.1.0), and from> there, the world. Right now, my laptop can only talk to the Multia. If I> want it to talk to another host on my network, I have to add a static> route to the host with the gateway set to the Multia, on the laptop. In> addition, I must add a static route to the laptop from the host, also> using the Multia as the gateway.>> For example, 192.168.1.1 is the gateway for my network to the> internet. 192.168.1.2 is the nameserver for my network – they’re both on> the same system, with .2 as an aliased address (don’t ask). To let my> laptop out on the internet, I have to do the following:>> On the laptop:> route add -host 192.168.1.1 gw 192.168.1.7> route add -host 192.168.1.2 gw 192.168.1.7 (for nameserver access)>> And on the internet gateway:> route add -host 192.168.1.13 gw 192.168.1.7The laptop must be ‘put on the same segment’ as the other machines. Howdoes your laptop connect to your Multia? slip, plip, ethernet?In case of ethernet: that should be easy. * Create a bridge device on the multia. * Enslave the ordinary ethernet device. * Enslave the ethernet device leading to the laptop.In case of plip it gets a bit trickier. Say that the plip which connectsthe laptop and the multia has addresses 192.168.10.1 (laptop) and192.168.10.2 (multia) assigned to them. * Create a bridge device on the multia * Enslave the ordinary ethernet interface * Enslave tap0 * Setup the plip link to the laptop. * Execute tap as follows: “tap /dev/tap0 192.168.10.1” * On the laptop: Setup the plip link. * Execute tap as follows: “tap /dev/tap0 192.168.10.2” * ifconfig tap0 to have the address under which you want to be seen on the network.In the plip case, we use the tap utility to build an ethernet tunnel overthe plip link (plip isn’t really ethernet). We then run the bridge overthe ethernet tunnel.For me, this worked fine.. a few months ago. Of course, I make noguarantee that it still works.. although it should. If it doesn’t, pleasecomplain to the list.greetings,Lennert