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From Vihar <vih1...@gmail.com>
Subject Re: DNS service on VR not responding
Date Mon, 21 Jul 2014 05:00:32 GMT
Hi ,

I would like you to comment second and third IP address I.e 4.2.2.2 and
8.8.8.8 and uncomment the first IP which is allocated to DNS and try to
resolve the internet. It might be resolving the queries from external DNS
server.

If you are not able to resolve the names from VR, check if the DNS service
is running properly for the IP which act as a DNS server.

Regards
Vihar
On Jul 21, 2014 10:19 AM, "Indra Pramana" <indra@sg.or.id> wrote:

> Hi Sanjeev,
>
> Good day to you, and thank you for your reply.
>
> Yes, I can resolve domains without any issues from within the VR itself.
>
> root@r-2606-VM:/etc# ping yahoo.com
> PING yahoo.com (98.139.183.24): 56 data bytes
> 64 bytes from 98.139.183.24: icmp_seq=0 ttl=47 time=250.473 ms
> 64 bytes from 98.139.183.24: icmp_seq=1 ttl=47 time=239.240 ms
> 64 bytes from 98.139.183.24: icmp_seq=2 ttl=45 time=247.605 ms
> 64 bytes from 98.139.183.24: icmp_seq=3 ttl=45 time=244.913 ms
> ^C--- yahoo.com ping statistics ---
> 4 packets transmitted, 4 packets received, 0% packet loss
> round-trip min/avg/max/stddev = 239.240/245.558/250.473/4.144 ms
>
> root@r-2606-VM:/etc# ping google.com
> PING google.com (74.125.68.102): 56 data bytes
> 64 bytes from 74.125.68.102: icmp_seq=0 ttl=52 time=1.353 ms
> 64 bytes from 74.125.68.102: icmp_seq=1 ttl=52 time=1.199 ms
> 64 bytes from 74.125.68.102: icmp_seq=2 ttl=52 time=1.268 ms
> 64 bytes from 74.125.68.102: icmp_seq=3 ttl=52 time=1.287 ms
> ^C--- google.com ping statistics ---
> 4 packets transmitted, 4 packets received, 0% packet loss
> round-trip min/avg/max/stddev = 1.199/1.277/1.353/0.055 ms
>
> The VR uses 8.8.8.8 and 8.8.4.4 to resolve domains.
>
> root@r-2606-VM:/etc# cat /etc/resolv.conf
> nameserver 8.8.8.8
> nameserver 8.8.4.4
>
> I can ping both name servers without any issues.
>
> root@r-2606-VM:/etc# ping 8.8.8.8
> PING 8.8.8.8 (8.8.8.8): 56 data bytes
> 64 bytes from 8.8.8.8: icmp_seq=0 ttl=52 time=4.693 ms
> 64 bytes from 8.8.8.8: icmp_seq=1 ttl=52 time=2.390 ms
> 64 bytes from 8.8.8.8: icmp_seq=2 ttl=52 time=2.523 ms
> 64 bytes from 8.8.8.8: icmp_seq=3 ttl=52 time=2.458 ms
> ^C--- 8.8.8.8 ping statistics ---
> 4 packets transmitted, 4 packets received, 0% packet loss
> round-trip min/avg/max/stddev = 2.390/3.016/4.693/0.969 ms
>
> root@r-2606-VM:/etc# ping 8.8.4.4
> PING 8.8.4.4 (8.8.4.4): 56 data bytes
> 64 bytes from 8.8.4.4: icmp_seq=0 ttl=52 time=2.649 ms
> 64 bytes from 8.8.4.4: icmp_seq=1 ttl=52 time=2.458 ms
> 64 bytes from 8.8.4.4: icmp_seq=2 ttl=52 time=2.436 ms
> 64 bytes from 8.8.4.4: icmp_seq=3 ttl=52 time=2.393 ms
> ^C--- 8.8.4.4 ping statistics ---
> 4 packets transmitted, 4 packets received, 0% packet loss
> round-trip min/avg/max/stddev = 2.393/2.484/2.649/0.098 ms
>
> Looking forward to your reply, thank you.
>
> Cheers.
>
>
>
>
> On Mon, Jul 21, 2014 at 12:18 PM, Sanjeev Neelarapu <
> sanjeev.neelarapu@citrix.com> wrote:
>
> > Hi,
> >
> > Can you check if the VR is able to resolve the domain names by pinging
> > from VR ?
> >
> > -Sanjeev
> >
> > -----Original Message-----
> > From: Vihar [mailto:vih1310@gmail.com]
> > Sent: Monday, July 21, 2014 5:43 AM
> > To: users@cloudstack.apache.org
> > Cc: dev@cloudstack.apache.org
> > Subject: RE: DNS service on VR not responding
> >
> > Hi,
> >
> > Yes, if I remove or comment out the first nameserver entry for the VR's
> > IP, and only leaving 8.8.8.8 and 8.8.4.4, guest VMs will be running fine
> > and will be able to resolve domains properly."
> >
> > Are you able to ping the first DNS server IP address that you commented
> > out?
> >
> > Regards
> > Vihar K
> >  On Jul 20, 2014 11:29 PM, "Santhosh Edukulla" <
> > santhosh.edukulla@citrix.com>
> > wrote:
> >
> > > Do a traceroute to an external domain say google.com from guest vm, as
> > > you mentioned below, both by commenting out vr ip and not, in
> > > resolv.conf, you may see the difference.
> > >
> > > "Yes, if I remove or comment out the first nameserver entry for the
> > > VR's IP, and only leaving 8.8.8.8 and 8.8.4.4, guest VMs will be
> > > running fine and will be able to resolve domains properly."
> > >
> > >
> > > Santhosh
> > > ________________________________________
> > > From: Indra Pramana [indra@sg.or.id]
> > > Sent: Sunday, July 20, 2014 1:48 PM
> > > To: users@cloudstack.apache.org
> > > Cc: dev@cloudstack.apache.org
> > > Subject: Re: DNS service on VR not responding
> > >
> > > 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
> > > > >
> > > >
> >
>

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