Sorry for the top post. But the problem is you have 2 interfaces in the same non connected network if .3 is on tap1 then add ip r a 172.20.0.3/32 dev tap1 ip r a 172.20.0.2/32 dev tap0 Your solution use vde to link the tap's or change the ip network so they are not the same Alex On Tue, Jul 15, 2008 at 07:57:04PM -0700, David Barrett wrote: > Can you suggest any way for me to configure my Ubuntu host or Debian > qemu guests such that the host can access each webserver running in both > guests? > > (I originally posted this to the qemu list, but I'm starting to think > it's not a qemu issue; rather, I think qemu is fine but I'm configuring > either my Debian guests or Ubuntu host wrong. I expect it's the sort of > thing that the right person will say "ah, obviously!" -- are you that > person?) > > In particular, I'm able to access the webserver on one image just fine, > but not the other: wget fails with "Connecting to 172.20.0.3:80... > failed: No route to host." > > Can you explain why and set me straight? > > I have two Debian qemu images (0 and 1), identical in all respects > except that image0 and image1 are configured to use static IPs > 172.20.0.2 and 172.20.0.3, respectively. I've launched both > simultaneously with the following commands: > > sudo qemu -kernel-kqemu -net nic,macaddr=00:00:00:00:00:00 -net tap > image0.raw > > sudo qemu -kernel-kqemu -net nic,macaddr=00:00:00:00:00:11 -net tap > image1.raw > > This creates two tap interfaces (0 and 1) on the Ubuntu host, curiously > with the same IP: > > tap0 Link encap:Ethernet HWaddr 00:ff:84:12:9d:72 > inet addr:172.20.0.1 Bcast:172.20.255.255 Mask:255.255.0.0 > inet6 addr: fe80::2ff:84ff:fe12:9d72/64 Scope:Link > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:18 errors:0 dropped:0 overruns:0 frame:0 > TX packets:36 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:500 > RX bytes:1336 (1.3 KB) TX bytes:4704 (4.5 KB) > > tap1 Link encap:Ethernet HWaddr 00:ff:af:9a:48:29 > inet addr:172.20.0.1 Bcast:172.20.255.255 Mask:255.255.0.0 > inet6 addr: fe80::2ff:afff:fe9a:4829/64 Scope:Link > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:24 errors:0 dropped:0 overruns:0 frame:0 > TX packets:34 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:500 > RX bytes:1656 (1.6 KB) TX bytes:4664 (4.5 KB) > > Furthermore, each image is configured with the following > /etc/network/interfaces: > > auto lo > iface lo inet loopback > allow-hotplug eth0 > iface eth0 inet static > address 172.20.0.2 <--- image1 has: address 172.20.0.3 > netmask 255.255.0.0 > gateway 172.20.0.1 > > > The upshot is "wget http://172.20.0.2"; and "wget http://172.20.0.3"; each > work fine inside their respective VMs. But each is unable to wget the > other's webserver. > > Furthermore, and most unusual, the host is able to wget image0's > webserver fine, but not image1. Specifically, the second wget fails as > follows: > > david@SonOfLappy:/svn/staging$ wget http://172.20.0.3 > --18:17:12-- http://172.20.0.3/ > => `index.html.1' > Connecting to 172.20.0.3:80... failed: No route to host. > david@SonOfLappy:/svn/staging$ > > The error message suggests some sort of routing problem, and the routing > table is: > > david@SonOfLappy:/svn/staging$ route > Kernel IP routing table > Destination Gateway Genmask Flags Metric Ref Use > Iface > 68.28.57.85 * 255.255.255.255 UH 0 0 0 ppp0 > 172.20.0.0 * 255.255.0.0 U 0 0 0 tap0 > 172.20.0.0 * 255.255.0.0 U 0 0 0 tap1 > default * 0.0.0.0 U 0 0 0 ppp0 > david@SonOfLappy:/svn/staging$ > > However, I'll admit I don't know much about the routing layer and thus > I'm not sure how to diagnose beyond that. But it seems very strange to > me to have two network interfaces with the same IP. > > With this in mind, if I shut down image0, the tap0 interface goes away, > and now the wget to image1 works fine. Again, this is suggesting > there's some kind of conflict where the second tap interface is somehow > "blocked" by the first. > > Anyway, that's as far as I can get. Can you suggest any way I can > configure the host's routing table in order to access image1? Or can I > manually create and share a single tap device? (I tried setting fd=tap0 > on the second launch command, but this had no effect.) > > (Incidentally, I also tried putting the second image onto a different > vlan by replacing adding "vlan=0" with "vlan=1" to each image's > respective launch command, but that had no effect -- the results were > identical.) > > Any suggestions? Thanks for any tips you can provide! > > -david > > > > -- > To UNSUBSCRIBE, email to debian-user-REQUEST@lists.debian.org with a > subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org > > -- But it does move! -- Galileo Galilei
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