<html> <head> <meta content="text/html; charset=ISO-8859-1" http-equiv="Content-Type"> </head> <body bgcolor="#FFFFFF" text="#000000"> Ups: I solved it now! On my kvm host the forward chain in iptables was set to "blocked". Changing it to "accept" solved the problem. Till this day I though, that the forward chain is only used in nat-environment. So I will take a deeper look in iptables now. Am 18.05.2012 12:29, schrieb Thorsten Göllner: <blockquote cite="mid:4FB62473.7050903@ovm-group.com" type="cite"> <meta content="text/html; charset=ISO-8859-1" http-equiv="Content-Type"> Yes, it was another typo. Sorry for that. My kvm host is attached to a switch with another 4 servers in our rack (it is mesh solution düsseldorf and not hetzner). I tried the following as suggested by serge: On another server connected to my switch I started tcpdump. On my guest I started a ping to the server with tcpdump. I can see, that the ping packet on the guest starts an arp request. My server (with running tcpdump) replies to the arp request correctly. In the guest I can see a correct arp table: ~# arp-n Address HWtype HWaddress Flags Mask Iface 113.203.209.161 ether 00:15:17:0e:6a:a9 C eth0 113.203.209.162 ether 00:22:15:41:13:23 C eth0 The first entry is that of my default gateway. The second one is that of my server running tcpdump. On the server running tcpdump (server name ist nostradamus2) I can see that: # tcpdump host 113.203.209.165 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes 12:28:19.370690 ARP, Request who-has nostradamus2 tell 165.209.203.113.static.inetbone.net, length 46 12:28:19.370703 ARP, Reply nostradamus2 is-at 00:22:15:41:13:23 (oui Unknown), length 28 So the question sould be: why does the guest not receive the arp reply from my server?! Am 18.05.2012 11:52, schrieb Michael Zoet: <blockquote cite="mid:4FB61BC8.9010001@zoet.de" type="cite"> <meta content="text/html; charset=ISO-8859-1" http-equiv="Content-Type"> <title></title> Hi, Am 18.05.2012 10:57, schrieb Thorsten Göllner: <blockquote cite="mid:4FB60EF8.1000207@ovm-group.com" type="cite"> <meta content="text/html; charset=ISO-8859-1" http-equiv="Content-Type"> Sorry, my fault. I had a typo. The broadcst is configured correctly: 113.203.209.191 Any other idea? </blockquote> yes but may be it is another typo: <blockquote cite="mid:4FB60EF8.1000207@ovm-group.com" type="cite"> <blockquote cite="mid:CAGt04nYoxCp99gK0OpsDJcp9440ow7o2Gpy78ZB1i02uzwOFkQ@mail.gmail.com" type="cite"> <div class="gmail_quote"> <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> <div bgcolor="#FFFFFF" text="#000000"> ON THE GUEST: ============= ~$ ifconfig eth0 Link encap:Ethernet HWaddr 52:54:00:d2:d1:73 inet addr:113.203.209.165 Bcast:213.203.09.191 Mask:255.255.255.224 [...] ~$ route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 113.203.209.161 0.0.0.0 UG 100 0 0 eth0 1213.203.209.160 0.0.0.0 255.255.255.224 U 0 0 0 eth0 </div> </blockquote> </div> </blockquote> </blockquote> An IP of 1213.203.209.160 in your default route does not exist in IPv4 ;-). The 1213 is much too high ;-) and I think the 2 should be deleted. But I also think your routing is not correct. In my opinion there should be 113.203.209.163(the IP of your KVM host) instead of 113.203.209.161 and 113.203.209.0 instead of 1213.203.209.16. But these are only guesses and it depends on how routing is done in your data center. (I think you are using Hetzner and Hetzner does not allow you to use their gateway with other MAC addresses than your KVM host!) Maybe it is a typo but may be not because you used the command "route -n". If you realy want some help you should post config files! It is easier to track problems. By, michael <fieldset class="mimeAttachmentHeader"></fieldset> </blockquote> <pre class="moz-signature" cols="72">-- Thorsten Göllner OVM Office Voice Media GmbH Herderstrasse 68 40237 Düsseldorf Tel.: +49(0)211 / 618 57 53 Fax: +49(0)211 / 618 57 54</pre> <fieldset class="mimeAttachmentHeader"></fieldset> </blockquote> <pre class="moz-signature" cols="72">-- Thorsten Göllner OVM Office Voice Media GmbH Herderstrasse 68 40237 Düsseldorf Tel.: +49(0)211 / 618 57 53 Fax: +49(0)211 / 618 57 54</pre> </body> </html>