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From Rafael Weingartner <rafaelweingart...@gmail.com>
Subject Re: DNS service on VR not responding
Date Sun, 20 Jul 2014 17:59:49 GMT
4. May I know how to enable the dnsmasq debug? Any documentation / steps on
how to do it? I believe I have to do it on the VR itself?
Sure you have to do that on VR itself.
You should edit the file /etc/dnsmasq.conf

Now I am not able to access my VR to see which property you should enable.
But, if you log into the VR and open the /etc/dnsmasq.conf, you should be
able to see a debug option commented.

You just need to uncomment it and restart the service.


On Sun, Jul 20, 2014 at 2:48 PM, Indra Pramana <indra@sg.or.id> wrote:

> Hi Santhosh,
>
> Good day to you, and thank you for your email.
>
> Traceroute packets seems to be dropped, I think it's by default. See result
> below:
>
> # traceroute X.X.X.2
> traceroute to X.X.X.2 (X.X.X.2), 30 hops max, 60 byte packets
>  1  * * *
>  2  * * *
>  3  * * *
>
> However, I am able to ping, and there is a response when I tried to telnet
> to port 53.
>
> 64 bytes from X.X.X.2: icmp_req=4 ttl=64 time=2.00 ms
> 64 bytes from X.X.X.2: icmp_req=5 ttl=64 time=0.291 ms
> 64 bytes from X.X.X.2: icmp_req=6 ttl=64 time=0.384 ms
> ^C
> --- X.X.X.2 ping statistics ---
> 6 packets transmitted, 6 received, 0% packet loss, time 4999ms
> rtt min/avg/max/mdev = 0.270/0.603/2.006/0.628 ms
>
> # telnet X.X.X.2 53
> Trying X.X.X.2...
> Connected to X.X.X.2.
> Escape character is '^]'.
>
> netstat -a on the VR shows the service is listening on domain port (53).
>
> tcp        0      0 r-2606-VM:domain        *:*                     LISTEN
>
> tcp        0      0 X.X.X.2:domain     *:*                     LISTEN
>
> udp   156992      0 r-2606-VM:domain        *:*
>
> udp   164032      0 X.X.X.2:domain     *:*
>
> Can you advise if there's anything else I need to check?
>
> Looking forward to your reply, thank you.
>
> Cheers.
>
>
>
>
> On Mon, Jul 21, 2014 at 1:17 AM, Santhosh Edukulla <
> santhosh.edukulla@citrix.com> wrote:
>
> > Run trace route from guest vms, the result will yield to the point where
> > packet drop is happening, could be a network acl rule issue, but tracert
> > command can lead to some answers.
> >
> > List running ports as well on VR, do a telnet to dns port on router from
> > guest vm to verify for its response.
> >
> > Santhosh
> > ________________________________________
> > From: Indra Pramana [indra@sg.or.id]
> > Sent: Sunday, July 20, 2014 1:06 PM
> > To: users@cloudstack.apache.org
> > Cc: dev@cloudstack.apache.org
> > Subject: Re: DNS service on VR not responding
> >
> > Hi Rafael,
> >
> > Good day to you, and thank you for your reply.
> >
> > Can't find anything wrong on dnsmasq.log / daemon.log, just some log
> > entries related to DHCP, nothing on DNS. I masked the IP addresses since
> > they are public.
> >
> > ===
> > Jul 20 16:21:51 r-2606-VM dnsmasq[3519]: DHCPDISCOVER(eth0) X.X.X.X
> > 06:62:a8:01:13:37
> > Jul 20 16:21:51 r-2606-VM dnsmasq[3519]: DHCPOFFER(eth0) X.X.X.X
> > 06:62:a8:01:13:37
> > Jul 20 16:21:51 r-2606-VM dnsmasq[3519]: DHCPREQUEST(eth0) X.X.X.X
> > 06:62:a8:01:13:37
> > Jul 20 16:21:51 r-2606-VM dnsmasq[3519]: DHCPACK(eth0) X.X.X.X
> > 06:62:a8:01:13:37 yyyyyy
> > Jul 20 16:23:53 r-2606-VM dnsmasq[3519]: DHCPINFORM(eth0) X.X.X.X
> > 06:43:4a:01:12:65
> > Jul 20 16:23:53 r-2606-VM dnsmasq[3519]: DHCPACK(eth0) X.X.X.X
> > 06:43:4a:01:12:65 zzzzzz
> > ===
> >
> > Yes, the guest VMs are having difficulties resolving domains into IP
> > addresses because of the problem on the VR's DNS server.
> >
> > $ host www.google.com X.X.X.X (where X.X.X.X is the IP address of the
> VR)
> > ;; connection timed out; no servers could be reached
> >
> > However, from within the VR, I am able to resolve domains just fine.
> >
> > Any advise where can I start troubleshooting this?
> >
> > Looking forward to your reply, thank you.
> >
> > Cheers.
> >
> >
> >
> > On Sun, Jul 20, 2014 at 11:26 PM, Rafael Weingartner <
> > rafaelweingartner@gmail.com> wrote:
> >
> > > Have you taken a look at dnsmasq.log in the VR ?
> > > What do you mean with not responding? The addresses are not being
> > resolved
> > > to ip addresses?
> > >
> > >
> > > On Sun, Jul 20, 2014 at 11:53 AM, Indra Pramana <indra@sg.or.id>
> wrote:
> > >
> > > > Dear all,
> > > >
> > > > All our guest VMs are having our virtual router (VR)'s IP address on
> > > > /etc/resolv.conf. In the past two weeks, I just realised that the DNS
> > > > service on the VR is not working, and doesn't respond to DNS queries
> > from
> > > > the DNS clients on the guest VM.
> > > >
> > > > I have tried to stop and start back the VR, but the problem persists.
> > > >
> > > > DHCP services seems to be running fine, only DNS services are not
> > > working.
> > > > From what I understand, both services are provided by dnsmasq,
> correct?
> > > >
> > > > Any advice on how can I resolve the problem?
> > > >
> > > > Looking forward to your reply, thank you.
> > > >
> > > > Cheers.
> > > >
> > >
> > >
> > >
> > > --
> > > Rafael Weingärtner
> > >
> >
>



-- 
Rafael Weingärtner

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