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-   -   dnsmasq in openvz slackware VE (http://www.linuxquestions.org/questions/slackware-14/dnsmasq-in-openvz-slackware-ve-4175446579/)

lambo69 01-21-2013 08:41 AM

dnsmasq in openvz slackware VE
 
Hi,

i'm in trouble with running dnsmasq as dhcp server in an openvz ve under slackware 14.0. DNS runs fine, dhcp doesn't work. No packet filters running, it shows the following behaviour:

In VE, ps ax and /var/log/messages show the following:
Code:

root@dns_dhcp:~> cat /etc/dnsmasq.conf
user=vmdnsmasq
group=vmdnsmasq

interface=venet0

#dhcp-authoritative
dhcp-range=192.168.0.190,192.168.0.200,96h

root@dns_dhcp:~> ps ax
 PID TTY      STAT  TIME COMMAND
    1 ?        Ss    0:00 init [3]
  69 ?        Ss    0:00 /usr/sbin/syslogd
  178 ?        Ss    0:00 /usr/sbin/sshd
  190 ?        Ss    0:00 /usr/sbin/crond -l notice
  195 ?        S      0:00 dnsmasq
  196 ?        Ss    0:00 sshd: root@pts/0
  198 pts/0    Ss    0:00 -bash
  210 pts/0    R+    0:00 ps ax

root@dns_dhcp:~> cat /var/log/messages
  Jan 21 12:50:37 dns_dhcp dnsmasq[195]: started, version 2.57  cachesize 150
  Jan 21 12:50:37 dns_dhcp dnsmasq[195]: compile time options: IPv6  GNU-getopt no-DBus I18N DHCP TFTP IDN
  Jan 21 12:50:37 dns_dhcp dnsmasq-dhcp[195]: DHCP, IP range 192.168.0.190 -- 192.168.0.200, lease time 4d
  Jan 21 12:50:37 dns_dhcp init: no more processes left in this runlevel
  Jan 21 12:50:37 dns_dhcp dnsmasq[195]: reading /etc/resolv.conf
  Jan 21 12:50:37 dns_dhcp dnsmasq[195]: using nameserver 5.9.237.206#53
  Jan 21 12:50:37 dns_dhcp dnsmasq[195]: using nameserver 217.171.190.12#53
  Jan 21 12:50:37 dns_dhcp dnsmasq[195]: read /etc/hosts - 15 addresses

...looks good for me, or is there anything wrong? If it's important: the IP range of the leases does not intersect with the IP addresses in /etc/hosts.

Now try to get an address by a client (physically a different machine):
Code:

root@multivac:~> dhclient eth0
root@multivac:~>

let's have a look at /var/log/messages:
Code:

root@multivac:~> cat /var/log/messages

<SNIP/>

Jan 21 14:22:14 multivac kernel: [16949.417422] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
Jan 21 14:22:18 multivac dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 15
Jan 21 14:22:33 multivac dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 7
Jan 21 14:22:40 multivac dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 15
Jan 21 14:22:55 multivac dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 16
Jan 21 14:23:11 multivac dhclient: No DHCPOFFERS received.
Jan 21 14:23:

Having a closer look with nmap to the VE running dnsmasq:
Code:

root@multivac:~> nmap 192.168.0.2

Starting Nmap 6.01 ( http://nmap.org ) at 2013-01-21 14:28 CET
Nmap scan report for dns_dhcp (192.168.0.2)
Host is up (0.00024s latency).
Not shown: 998 closed ports
PORT  STATE SERVICE
22/tcp open  ssh
53/tcp open  domain
MAC Address: xx:xx:xx:xx:xx:xx (Netronix)

Nmap done: 1 IP address (1 host up) scanned in 0.79 seconds

Shouldn't port 67 be open?

I get the same result from other machines that try to get a lease.

Has anyone an idea or a hint?

confused
lambo

hotchili 01-22-2013 06:26 AM

Hello,

a quick search shows that for dhcp to work you need to setup a veth network device, not the standard venet.

http://wiki.openvz.org/DHCP
http://wiki.openvz.org/Virtual_Ethernet_device

Maybe that is why it isn't working. Good luck :)

lambo69 01-25-2013 11:25 AM

Thank you for the hint. Unfortunately, it still doesn't work after switching to a veth.
tcpdump on the openvz host shows, that it (the host) receives the DISCOVER requests from the client, but a tcpdump inside the VE on eth0 shows: nothing. The VE responds to pings and DNS requests via it's eth0 from the outside.
On the host, the following is set:
Code:

root@openvzhost:~> cat /proc/sys/net/ipv4/conf/eth0/forwarding
1
root@openvzhost:~> cat /proc/sys/net/ipv4/conf/eth0/proxy_arp
1
root@openvzhost:~> cat /proc/sys/net/ipv4/conf/veth9999.0/forwarding
1
root@openvzhost:~> cat /proc/sys/net/ipv4/conf/veth9999.0/proxy_arp
1

Bridging with bridge-utils has also failed.

lambo


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