Date: Thu, 14 May 2009 13:39:17 +0200 From: "marco\.borsatino\@poste\.it" <marco.borsatino@poste.it> To: freebsd-questions@freebsd.org Cc: nvass9573@gmx.com Subject: virtual network with qemu Message-ID: <KJMTPH$2D2A1378CB676588DEE0977D130EFCFA@poste.it>
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First, thank you. You are right, qemu has an internal DHCP server, which should be perfect = for me, becuse I would like to emulate a network without any contact with= external (real) world. The problem is that my virtual PC can't ping the = gateway. For my idea (this is just a way to study a project for a network= without a real network) the communication is intended only among virtual= PCs. But If I can't contact the (virtual) gateway will it be possible to= contact another virtual PC on a different subnet? Or even on the same su= bnet? In my idea I would like to create a little but complex net with one= master controller, a slave controller, a little number of client belongi= ng to different subnets. Maybe with or without a DHCP server. Marco ---------- Original Header ----------- >From : "Nikos Vassiliadis" nvass9573@gmx.com To : "marco.borsatino@poste.it" marco.borsatino@poste.it Cc : freebsd-questions@freebsd.org Date : Thu, 14 May 2009 11:28:59 +0300 Subject : Re: virtual network with qemu > marco.borsatino@poste.it wrote: > > When the installation program asked for information about network con= figuration, as a > > first step, I chose DHCP configuration and, as usualy, the network ha= s been set > > like this: > > IP 10.0.2.15/255.255.255.0 > > If I recall correctly qemu has a built-in DHCP server. > That's the one that served you, not a "real" DHCP server > running on your LAN, that is, you are not in any way connected > to the "real" network. > > > #qemu -L /usr/local/share/qemu -localtime -net nic,macaddr=3D00:15:f2= :44:2d:01 -net socket,mcast=3D230.0.0.1:1234 -hda pc01.img -cdrom /dev/ac= d0 & > > but the network in the guest system does not work. > > It makes sense, that the multicast option will work > between virtual hosts only. That is, it uses multicast > to provide a virtual broadcast domain, which appears to > the host operating system as a ethernet device. > > > ifconfig in the guest system tells: > > #ifconfig -a > > ed0: flags=3D8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mt= u 1500 > > ether 00:15:f2:44:2d:01 > > media: Ethernet 10baseT/UTP <full-duplex> > > plip0: ... > > lo0: ... > > If I try: > > #ping 10.0.2.2 (the gateway) > > all packets are lost. For this reason, I've tryed a static IP configu= ration like this: > > IP 10.0.2.4/255.255.255.0 > > gateway 10.0.2.2 > > nameserver 10.0.2.3 > > but the gateway does not respond. So it is useless to try with a seco= nd guest system. > > No, infact it's the exact opposite. This type of device > will work *only* if you add another virtual system. > > To get connected to the "real" network, you must use tap > devices. Correction: > Browsing the qemu's wiki I found out that there is a newer > and simpler approach that I am not familiar with: > http://calamari.reverse-dns.net:980/cgi-bin/moin.cgi/user-net > > So, if you do want internet access, just remove all network > associated options and it will work automagically. If you just > want to connect guest systems together use multicast or socket > or ... > > HTH, Nikos > >
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