[Dnsmasq-discuss] UDP queries to DNS fail

Mike Owens mike at transpireinc.com
Sat Jan 7 01:21:11 GMT 2012 

I have an issue that's driving me nuts. I have dnsmasq installed and DHCP
is working fine. I can make DNS queries over TCP and they work fine. Normal
DNS requests over UDP fail if done from a remote machine but succeed if
done locally. First thing I did was check the firewall. I have gone so far
as to completely remove UFW so that there is no doubt. I can get a reply
using nc -u -z 192.168.1.100 53 from a remote machine and dig +tcp
www.yahoo.com @serverip also succeeds.

Config file:

> domain-needed
> bogus-priv
> strict-order
> server=192.168.1.100
> interface=eth0
> domain=transpireinc.com
> dhcp-range=192.168.1.2,192.168.1.99,255.255.255.0,12h
> dhcp-option=3,192.168.1.1
> dhcp-authoritative
> bogus-nxdomain=64.94.110.11
> log-facility=/var/log/dnsmasq
> log-queries
> log-dhcp
>
>

netstat -lpn output:

> tcp        0      0 0.0.0.0:53              0.0.0.0:*
> LISTEN      932/dnsmasq
> tcp6       0      0 :::53                   :::*
> LISTEN      932/dnsmasq
> udp        0      0 0.0.0.0:53              0.0.0.0:*
> 932/dnsmasq
> udp        0      0 0.0.0.0:67              0.0.0.0:*
> 932/dnsmasq
> udp6       0      0 :::53
> :::*                                932/dnsmasq


Log snippet from today. All the successful queries occurred over TCP:

> Jan  6 16:20:08 dnsmasq[823]: started, version 2.57 cachesize 150
> Jan  6 16:20:08 dnsmasq[823]: compile time options: IPv6 GNU-getopt DBus
> I18N DHCP TFTP IDN
> Jan  6 16:20:08 dnsmasq-dhcp[823]: DHCP, IP range 192.168.1.2 --
> 192.168.1.99, lease time infinite
> Jan  6 16:20:08 dnsmasq[823]: using nameserver 192.168.1.100#53
> Jan  6 16:20:08 dnsmasq[823]: reading /var/run/dnsmasq/resolv.conf
> Jan  6 16:20:08 dnsmasq[823]: using nameserver 68.87.85.102#53
> Jan  6 16:20:08 dnsmasq[823]: using nameserver 68.87.69.150#53
> Jan  6 16:20:08 dnsmasq[823]: using nameserver 68.87.64.146#53
> Jan  6 16:20:08 dnsmasq[823]: using nameserver 192.168.1.1#53
> Jan  6 16:20:08 dnsmasq[823]: using nameserver 192.168.1.100#53
> Jan  6 16:20:08 dnsmasq[823]: using nameserver 192.168.1.100#53
> Jan  6 16:20:08 dnsmasq[823]: read /etc/hosts - 12 addresses
> Jan  6 16:20:43 dnsmasq[840]: query[A] debian.org from 192.168.1.102
> Jan  6 16:20:43 dnsmasq[840]: forwarded debian.org to 192.168.1.100
> Jan  6 16:20:43 dnsmasq[840]: reply debian.org is 206.12.19.7
> Jan  6 16:20:43 dnsmasq[840]: reply debian.org is 128.31.0.51
> Jan  6 16:37:10 dnsmasq[856]: query[A] www.yahoo.com from 192.168.1.102
> Jan  6 16:37:10 dnsmasq[856]: forwarded www.yahoo.com to 192.168.1.100
> Jan  6 16:37:10 dnsmasq[856]: reply www.yahoo.com is <CNAME>
> Jan  6 16:37:10 dnsmasq[856]: reply fp3.wg1.b.yahoo.com is <CNAME>
> Jan  6 16:37:10 dnsmasq[856]: reply any-fp3-lfb.wa1.b.yahoo.com is <CNAME>
> Jan  6 16:37:10 dnsmasq[856]: reply any-fp3-real.wa1.b.yahoo.com is
> 72.30.2.43
> Jan  6 16:37:10 dnsmasq[856]: reply any-fp3-real.wa1.b.yahoo.com is
> 98.137.149.56
> Jan  6 16:40:14 dnsmasq[882]: query[A] www.yahoo.com from 192.168.1.102
> Jan  6 16:40:14 dnsmasq[882]: forwarded www.yahoo.com to 192.168.1.100
> Jan  6 16:40:14 dnsmasq[882]: reply www.yahoo.com is <CNAME>
> Jan  6 16:40:14 dnsmasq[882]: reply fp3.wg1.b.yahoo.com is <CNAME>
> Jan  6 16:40:14 dnsmasq[882]: reply any-fp3-lfb.wa1.b.yahoo.com is <CNAME>
> Jan  6 16:40:14 dnsmasq[882]: reply any-fp3-real.wa1.b.yahoo.com is
> 98.137.149.56
> Jan  6 16:40:14 dnsmasq[882]: reply any-fp3-real.wa1.b.yahoo.com is
> 72.30.2.43
> Jan  6 17:06:56 dnsmasq[823]: exiting on receipt of SIGTERM
> Jan  6 17:06:58 dnsmasq[932]: started, version 2.57 cachesize 150
> Jan  6 17:06:58 dnsmasq[932]: compile time options: IPv6 GNU-getopt DBus
> I18N DHCP TFTP IDN
> Jan  6 17:06:58 dnsmasq-dhcp[932]: DHCP, IP range 192.168.1.2 --
> 192.168.1.99, lease time 12h
> Jan  6 17:06:58 dnsmasq[932]: using nameserver 192.168.1.100#53
> Jan  6 17:06:58 dnsmasq[932]: reading /var/run/dnsmasq/resolv.conf
> Jan  6 17:06:58 dnsmasq[932]: using nameserver 68.87.85.102#53
> Jan  6 17:06:58 dnsmasq[932]: using nameserver 68.87.69.150#53
> Jan  6 17:06:58 dnsmasq[932]: using nameserver 68.87.64.146#53
> Jan  6 17:06:58 dnsmasq[932]: using nameserver 192.168.1.1#53
> Jan  6 17:06:58 dnsmasq[932]: using nameserver 192.168.1.100#53
> Jan  6 17:06:58 dnsmasq[932]: using nameserver 192.168.1.100#53
> Jan  6 17:06:58 dnsmasq[932]: read /etc/hosts - 12 addresses
> Jan  6 17:07:34 dnsmasq[950]: query[A] www.yahoo.com from 192.168.1.102
> Jan  6 17:07:34 dnsmasq[950]: forwarded www.yahoo.com to 192.168.1.100
> Jan  6 17:07:34 dnsmasq[950]: reply www.yahoo.com is <CNAME>
> Jan  6 17:07:34 dnsmasq[950]: reply fp3.wg1.b.yahoo.com is <CNAME>
> Jan  6 17:07:34 dnsmasq[950]: reply any-fp3-lfb.wa1.b.yahoo.com is <CNAME>
> Jan  6 17:07:34 dnsmasq[950]: reply any-fp3-real.wa1.b.yahoo.com is
> 98.137.149.56
> Jan  6 17:07:34 dnsmasq[950]: reply any-fp3-real.wa1.b.yahoo.com is
> 72.30.2.43
>

The only thing keeping this server from going live is this UDP problem.

Thanks
Mike

>
>
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