From: Nikolaus H. <nha...@sc...> - 2003-12-27 16:00:35
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Hi, Thank you, my machine itself works now very well with network but now I have a few questions about "fine tuning": 1.) For networking I use a bridge, based on David's tutorial. But which MAC Address does the eth0 interface inside the UML have? Is this a random one? Is it possible to set this address for myself? Wouldn't it be then very simple to "fake" MAC addresses in order to pass MAC filter and so on? 2.) Goes *every* traffic through the bridge? (I mean broadcasts and similar). Could I configure my UML with DHCP when in the other network outside would be a DHCP server? Could the UML serve a DHCP from inside the machine for the whole Ethernet network outside? 3.) Now, I've the following configuration that works: Host: 2.6.0 stable without any patch UML: 2.4.20-8uml Root: debian-root image from the homepage. I've compiled the driver for hostfs into the uml kernel image. When I do a # mount none /mnt -t hostfs then I get the error: "Child nnnn exited with signal nn" The UML crashed; the only thing that works is killall -9 linux This was the same error I got when useing the tomfs filesystem. However, I read that hostfs is incompatible with kernel 2.6 but I have 2.6 only as HOST and as UML I have 2.4.20 anyways. hostfs is very important to me because I need the files for my personal use on the host machine and want to serve the same files into the UML via Samba. 4.) Is the SKAS mode integrated in kernel 2.6.0 stable? If not, which patch shall I take? My host system is a "productive" system where I do not want to have unstable software. Is the patch unstable? What's happening when I apply "an official" patch from www.kernel.org to my host sources? Does this work? 5.) Is there a really cool way to use the UML as background process? When everything is finished, I want to start the UML on system bootup. I have set up ssh and the network, therefor I do not need a console. Things like linux &>/dev/null or linux & 2>/dev/null did not work. First, I got kernel messages anyway and Second, if I closed the shell, the linux process died. Are there "elegant" ways to handle this? Thanks again, Niki |
From: Ali C. <al...@al...> - 2003-12-27 16:09:57
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Best way to boot UML into the background is probably to run it using 'screen'. -----Original Message----- From: use...@li... [mailto:use...@li...]On Behalf Of Nikolaus Hammler Sent: 27 December 2003 16:00 To: use...@li... Subject: [uml-user] Fine tuning for UML's Hi, Thank you, my machine itself works now very well with network but now I have a few questions about "fine tuning": 1.) For networking I use a bridge, based on David's tutorial. But which MAC Address does the eth0 interface inside the UML have? Is this a random one? Is it possible to set this address for myself? Wouldn't it be then very simple to "fake" MAC addresses in order to pass MAC filter and so on? 2.) Goes *every* traffic through the bridge? (I mean broadcasts and similar). Could I configure my UML with DHCP when in the other network outside would be a DHCP server? Could the UML serve a DHCP from inside the machine for the whole Ethernet network outside? 3.) Now, I've the following configuration that works: Host: 2.6.0 stable without any patch UML: 2.4.20-8uml Root: debian-root image from the homepage. I've compiled the driver for hostfs into the uml kernel image. When I do a # mount none /mnt -t hostfs then I get the error: "Child nnnn exited with signal nn" The UML crashed; the only thing that works is killall -9 linux This was the same error I got when useing the tomfs filesystem. However, I read that hostfs is incompatible with kernel 2.6 but I have 2.6 only as HOST and as UML I have 2.4.20 anyways. hostfs is very important to me because I need the files for my personal use on the host machine and want to serve the same files into the UML via Samba. 4.) Is the SKAS mode integrated in kernel 2.6.0 stable? If not, which patch shall I take? My host system is a "productive" system where I do not want to have unstable software. Is the patch unstable? What's happening when I apply "an official" patch from www.kernel.org to my host sources? Does this work? 5.) Is there a really cool way to use the UML as background process? When everything is finished, I want to start the UML on system bootup. I have set up ssh and the network, therefor I do not need a console. Things like linux &>/dev/null or linux & 2>/dev/null did not work. First, I got kernel messages anyway and Second, if I closed the shell, the linux process died. Are there "elegant" ways to handle this? Thanks again, Niki ------------------------------------------------------- This SF.net email is sponsored by: IBM Linux Tutorials. Become an expert in LINUX or just sharpen your skills. Sign up for IBM's Free Linux Tutorials. Learn everything from the bash shell to sys admin. Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click _______________________________________________ User-mode-linux-user mailing list Use...@li... https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user |
From: <s-...@rh...> - 2003-12-27 21:58:15
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> 1.) For networking I use a bridge, based on David's tutorial. But which > MAC Address does the eth0 interface inside the UML have? Is this a random > one? Is it possible to set this address for myself? I'm not sure how the MAC address is assigned, but I believe you can set it yourself in the eth0= kernel argument. See the networking docs. > Wouldn't it be then very simple to "fake" MAC addresses > in order to pass MAC filter and so on? I think so. I'm not sure what you could do about that other than using a different mode of networking and use iptables to filter by interface. > 2.) Goes *every* traffic through the bridge? (I mean > broadcasts and similar). Could I configure my UML with > DHCP when in the other network outside would be a DHCP > server? > Could the UML serve a DHCP from inside the machine for > the whole Ethernet network outside? Yes yes and yes. > 3.) Now, I've the following configuration that works: > I've compiled the driver for hostfs into the uml > kernel image. > When I do a > # mount none /mnt -t hostfs > then > I get the error: > "Child nnnn exited with signal nn" Not sure about this. Maybe someone else knows. > 4.) Is the SKAS mode integrated in kernel 2.6.0 stable? > If not, which patch shall I take? My host system is a "productive" > system where I do not want to have unstable software. Is the > patch unstable? What's happening when I apply "an official" patch > from www.kernel.org to my host sources? Does this work? I've been running skas3+official 2.4 kernels and haven't had any stability problems. > 5.) Is there a really cool way to use the UML as background > process? When everything is finished, I want to start the UML > on system bootup. I have set up ssh and the network, therefor > I do not need a console. > Things like > linux &>/dev/null > or > linux & 2>/dev/null > did not work. > First, I got kernel messages anyway and > Second, if I closed the shell, the linux process died. > > Are there "elegant" ways to handle this? You can start the uml within screen as Ali Cambell mentioned. If you want it to work like you are trying above, start uml like linux con0=null > /dev/null & That will silence it completely and uml won't exit when you close the terminal. -Steve |
From: David C <da...@ho...> - 2003-12-30 18:49:53
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On Saturday 27 December 2003 4:00 pm, Nikolaus Hammler wrote: > Thank you, my machine itself works now very well > with network but now I have a few questions about > "fine tuning": > > 1.) For networking I use a bridge, based on David's > tutorial. But which MAC Address does the eth0 interface > inside the UML have? Is this a random one? > Is it possible to set this address for myself? Apologies Nikolaus, I seem to have missed your mail. I don't think I've replied to this one but if I have, please disregard. Yes, the MAC address is random but you can specify it yourself on the commandline. I forget the exact syntax but see the networking section on http://user-mode-linux.sf.net. > Wouldn't it be then very simple to "fake" MAC addresses > in order to pass MAC filter and so on? Not if you only allow outgoing frames from the MAC address the UML should have. You can do this using ebtables. If you do this, even if the UML fakes its MAC address (or configures itself with another, etc) the frames wont pass your filter. Also remember that whilst MAC spoofing is theoretically (and practically) possible and also quite easy, without some form of ARP spoofing or spoiling you wont be able to pick up any replies. I don't honestly know how the bridging code in the kernel would deal with a situation where a UML on one port has a MAC address and another UML on a different port fakes the MAC of the other machine. I say this because bridges are "intelligent" and "learn" what is plugged into where. Whether they do so from ARP replies or outgoing frames, I don't know. I would imagine the former. > 2.) Goes *every* traffic through the bridge? (I mean > broadcasts and similar). Could I configure my UML with > DHCP when in the other network outside would be a DHCP > server? Certainly. DHCP is just a broadcast which should go through the bridge fine. > Could the UML serve a DHCP from inside the machine for > the whole Ethernet network outside? Again, I'm fairly certain this should be possible. Give it a go, please let me know your success. David |