[Dnsmasq-discuss] local domain added when forwarding to upstream DNS servers

[Lixus Zoran]

Hi,

> > That is surprising me, this querie not even gets forwarded to the upsteam server.

That is exact the bug I am complaining about.

 
> Yes, puzzling. Try adding 'log-queries' to your /etc/dnsmasq.conf and 
> see what gets logged when you repeat this.


# nslookup lists.thekelleys.org.uk.
Server:         127.0.0.1
Address:        127.0.0.1#53
** server can't find lists.thekelleys.org.uk: REFUSED

This gets logged to /var/log/messages with log-queries enabled.

  May  4 16:14:28 mydesktop dnsmasq[8385]: query[A] lists.thekelleys.org.uk from 127.0.0.1
  May  4 16:14:28 mydesktop dnsmasq[8385]: query[A] lists.thekelleys.org.uk from 127.0.0.1

This is what goes over the wire:
# tshark -i any port 53

  4.827968    127.0.0.1 -> 127.0.0.1    DNS Standard query A lists.thekelleys.org.uk
  4.828089    127.0.0.1 -> 127.0.0.1    DNS Standard query response, Refused
  4.828383    127.0.0.1 -> 127.0.0.1    DNS Standard query A lists.thekelleys.org.uk
  4.828448    127.0.0.1 -> 127.0.0.1    DNS Standard query response, Refused


So it's very clear that dnsmasq is not forwarding to the upstream server
instead it "refuses" the querie.

I believe it's a bug.

I ran "strace -f -p <pid of dnamasq>" while running the nslookup, not sure if this is of any help:

8385  select(7, [3 4 5 6], [], [], NULL) = 1 (in [4])
8385  time(NULL)                        = 1241447007
8385  stat64("/etc/resolvconf/resolv.conf.d/upstream", {st_mode=S_IFREG|0644, st_size=24, ...}) = 0
8385  stat64("/var/run/dnsmasq/resolv.conf", {st_mode=S_IFREG|0644, st_size=21, ...}) = 0
8385  recvmsg(4, {msg_name(16)={sa_family=AF_INET, sin_port=htons(51220), sin_addr=inet_addr("127.0.0.1")}, msg_iov(1)=[{"\206\343\1\0\0\1\0\0\0\0\0\0\5lists\nthekelleys\3or"..., 1280}], msg_controllen=24, {cmsg_len=24, cmsg_level=SOL_IP, cmsg_type=, ...}, msg_flags=0}, 0) = 41
8385  ioctl(4, SIOCGIFNAME, {ifr_index=1, ifr_name="lo"}) = 0
8385  time(NULL)                        = 1241447007
8385  stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2309, ...}) = 0
8385  write(8, "<31>May  4 16:23:27 dnsmasq[8385"..., 83) = 83
8385  sendmsg(4, {msg_name(16)={sa_family=AF_INET, sin_port=htons(51220), sin_addr=inet_addr("127.0.0.1")}, msg_iov(1)=[{"\206\343\201\205\0\1\0\0\0\0\0\0\5lists\nthekelleys\3o"..., 41}], msg_controllen=24, {cmsg_len=24, cmsg_level=SOL_IP, cmsg_type=, ...}, msg_flags=0}, 0) = 41
8385  select(7, [3 4 5 6], [], [], NULL) = 1 (in [4])
8385  time(NULL)                        = 1241447007
8385  recvmsg(4, {msg_name(16)={sa_family=AF_INET, sin_port=htons(41764), sin_addr=inet_addr("127.0.0.1")}, msg_iov(1)=[{"\310\267\1\0\0\1\0\0\0\0\0\0\5lists\nthekelleys\3or"..., 1280}], msg_controllen=24, {cmsg_len=24, cmsg_level=SOL_IP, cmsg_type=, ...}, msg_flags=0}, 0) = 41
8385  ioctl(4, SIOCGIFNAME, {ifr_index=1, ifr_name="lo"}) = 0
8385  time(NULL)                        = 1241447007
8385  stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2309, ...}) = 0
8385  write(8, "<31>May  4 16:23:27 dnsmasq[8385"..., 83) = 83
8385  sendmsg(4, {msg_name(16)={sa_family=AF_INET, sin_port=htons(41764), sin_addr=inet_addr("127.0.0.1")}, msg_iov(1)=[{"\310\267\201\205\0\1\0\0\0\0\0\0\5lists\nthekelleys\3o"..., 41}], msg_controllen=24, {cmsg_len=24, cmsg_level=SOL_IP, cmsg_type=, ...}, msg_flags=0}, 0) = 41
8385  select(7, [3 4 5 6], [], [], NULL <unfinished ...>




> Isn't a name service cache daemon redundant on a machine using Dnsmasq 
> for local resolution?

For hosts yes, but it's also caching user and group information, therefore I am using
nscd but for this test it's now disabled.

Best Regards
Lixus