[Dnsmasq-discuss] Strange behavior when making the nameserver machine use dnsmasq

[Zack Little]

Hello.  I have searched the archive and cannot find any information about this.
 
I followed this statement when setting up dnsmasq:
 
"Making the nameserver machine use dnsmasq.
In the simple configuration described above, processes local to the machine will not use dnsmasq, since they get their information about which nameservers to use from /etc/resolv.conf, which is set to the upstream nameservers. To fix this, simply replace the nameserver in /etc/resolv.conf with the local address 127.0.0.1 and give the address(es) of the upstream nameserver(s) to dnsmasq directly. You can do this using either the server option, or by putting them into another file, and telling dnsmasq about its location with the resolv-file option."

dnsmasq is launched as follows:
 
/bin/dnsmasq -q -k -c 0 -N -o -r /ramdisk/resolv.conf

The /ramdisk/resolv.conf contains the following:
nameserver 10.102.1.25     
nameserver 135.54.66.1     
nameserver 209.183.35.23
nameserver 209.183.35.24


When dnsmasq starts it logs the following:

<30>Mar 26 16:42:57 dnsmasq[2889]: started, version 2.43 cache disabled 
<30>Mar 26 16:42:57 dnsmasq[2889]: compile time options: IPv6 GNU-getopt no-ISC-leasefile no-DBus no-I18N TFTP 
<30>Mar 26 16:42:57 dnsmasq[2889]: reading /ramdisk/resolv.conf 
<30>Mar 26 16:42:57 dnsmasq[2889]: using nameserver 209.183.35.24#53 
<30>Mar 26 16:42:57 dnsmasq[2889]: using nameserver 209.183.35.23#53 
<30>Mar 26 16:42:57 dnsmasq[2889]: using nameserver 135.54.66.1#53 
<30>Mar 26 16:42:57 dnsmasq[2889]: using nameserver 10.102.1.25#53 
<30>Mar 26 16:42:57 dnsmasq[2889]: read /etc/hosts - 6 addresses


>From a Windows Vista PC *behind* the device running dnsmasq if I send one ping (ping -n 1)
dnsmasq logs the following:

 

<31>Mar 26 16:43:06 dnsmasq[2889]: query[A] www.google.com from 10.77.7.5 
<31>Mar 26 16:43:06 dnsmasq[2889]: forwarded www.google.com to 10.102.1.25 
<31>Mar 26 16:43:07 dnsmasq[2889]: query[A] www.google.com from 10.77.7.5 
<31>Mar 26 16:43:07 dnsmasq[2889]: forwarded www.google.com to 135.54.66.1 
<31>Mar 26 16:43:08 dnsmasq[2889]: query[A] www.google.com from 10.77.7.5 
<31>Mar 26 16:43:08 dnsmasq[2889]: forwarded www.google.com to 209.183.35.23 
<31>Mar 26 16:43:08 dnsmasq[2889]: reply www.google.com is <CNAME> 
<31>Mar 26 16:43:08 dnsmasq[2889]: reply www.l.google.com is 66.102.7.104 
<31>Mar 26 16:43:08 dnsmasq[2889]: reply www.l.google.com is 66.102.7.99

 

The first DNS, 10.102.1.25, does eventually respond with a 'standard query response, server failure', but not until 16:43:21.98.  The second dns, 135.54.66.1, doesn't respond.  The third DNS, 209.183.35.23, responds with an answer.  This all works properly and the name is resolved.  dnsmasq appears to be waiting approximately one second before trying the next DNS.

 

On the device dnsmasq is running on the /etc/resolv.conf only contains "nameserver 127.0.0.1".

 

The problem occurs when a process on the same device dnsmasq is running on tries to resolve a name.  A 'ping -c 1 www.google.com' from the command line on the device causes dnsmasq to log the following:

 

<31>Mar 26 16:43:29 dnsmasq[2889]: query[A] www.google.com from 127.0.0.1 
<31>Mar 26 16:43:29 dnsmasq[2889]: forwarded www.google.com to 10.102.1.25 
<31>Mar 26 16:43:39 dnsmasq[2889]: query[A] www.google.com from 127.0.0.1 
<31>Mar 26 16:43:39 dnsmasq[2889]: forwarded www.google.com to 10.102.1.25

 

As you can see the request was sent to loopback and dnsmasq handled it.  That is what is expected.  However, dnsmasq is acting very differently.  After sending a request to the first DNS it waits 10 seconds instead of 1 second for the second attempt.  Instead of using the second DNS for the next attempt it again uses the first DNS.  The first DNS request eventually is answered at 16:43:45.06.

 

Because only the first DNS is used (and also because the retries are so far apart) the device that is running dnsmasq is not able to resolve names.  

 

Is this a known bug?

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