[Users] Running DHCP on VPS, ( on a router.. )

Dariush Pietrzak ml-openvz-eyck at kuszelas.com
Fri Sep 28 08:14:29 EDT 2007


> DHCP server should work fine with veth bridged to host eth0 interface.
> Can you reproduce your issue when server doesn't reply?
 it looks like this:

HN: tcpdump -n -i eth0.107
08:16:19.401880 00:1b:d4:7e:76:2a > 01:00:0c:cc:cc:cd SNAP Unnumbered, ui, Flags [Command], length 50
08:16:21.154240 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 00:1b:d5:2c:bf:38, length 308
08:16:21.185096 IP 192.168.8.254.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 300
08:16:21.187344 arp who-has 192.168.9.254 tell 192.168.9.97


HN: tcpdump -n -i br107
08:16:19.401880 00:1b:d4:7e:76:2a > 01:00:0c:cc:cc:cd SNAP Unnumbered, ui, Flags [Command], length 50
08:16:21.154240 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 00:1b:d5:2c:bf:38, length 308
08:16:21.185096 IP 192.168.8.254.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 300
08:16:21.187344 arp who-has 192.168.9.254 tell 192.168.9.97

and finally, from inside the vps:
VPS: tcpdump -n -i eth0
08:16:19.401886 00:1b:d4:7e:76:2a > 01:00:0c:cc:cc:cd SNAP Unnumbered, ui, Flags [Command], length 50
08:16:21.185110 IP 192.168.8.254.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 300
08:16:21.187356 arp who-has 192.168.9.254 tell 192.168.9.97
08:16:21.188600 arp who-has 192.168.8.1 tell 192.168.9.97

 as you can see, broadcast request from dhcp client is missing, but strangely enough, the reply
is clearly visible.

 I also tried doing something like this to verify the software inside VPS: I chroot to ..../vz/private/107/
and then launch the dhcpd against br107, and then it works as expected.

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