dnsmasq local network works for some but hostnames are not resolving for others

Question

I have set up a local network and it seems that some of us can use it properly while others can't. The problem seems to be that the local hostnames I setup don't get resolved for everyone.

To overview how the network is setup:

I am running an Ubuntu 10.01 server using dnsmasq, this server is setup to act as our primary DNS server, configured via our router.

dnsmasq is configured using the options of

domain-needed
bogus-priv

I use the /etc/hosts file to determain the hostnames

192.168.1.10    ra.xsi
192.168.1.10    test.xsi

From my machine:

If I dig the hostnames they resolve properly

; <<>> DiG 9.4.3-P1 <<>> ra.xsi
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 61671
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;ra.xsi.                IN  A

;; ANSWER SECTION:
ra.xsi.         0   IN  A   192.168.1.10

;; Query time: 9 msec
;; SERVER: 192.168.1.10#53(192.168.1.10)
;; WHEN: Wed Nov  9 12:28:34 2011
;; MSG SIZE  rcvd: 40

Ping also works:

PING ra.xsi (192.168.1.10): 56 data bytes
64 bytes from 192.168.1.10: icmp_seq=0 ttl=64 time=0.834 ms
64 bytes from 192.168.1.10: icmp_seq=1 ttl=64 time=0.699 ms
^C
--- ra.xsi ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.699/0.766/0.834/0.068 ms

And login via SSH works using the hostname.

For those that cannot connect using hostnames, if I dig from their machine it appears the name is being resolved, but they cannot ping, SSH or http access the hostname.

; <<>> DiG 9.6.0-APPLE-P2 <<>> ra
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12554
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;ra.xsi.                IN    A

;; ANSWER SECTION:
ra.xsi.           0    IN    A    192.168.1.10

;; Query time: 8 msec
;; SERVER: 192.168.1.10#53(192.168.1.10)
;; WHEN: Wed Nov  9 12:05:50 2011
;; MSG SIZE  rcvd: 36

I've been banging my head at this and just can't seem to figure it out.

Answer 1

I would suspect the hosts that can't find the hostname are using some other DNS servers. There are a few reasons for this:

• They have static addresses. These hosts will not received their DNS servers from the DHCP server (router).
• Some hosts are getting their address from a DHCP server which isn't configured to send your DNS server in its response. This could be dnsmasq if you haven't disabled DHCP.
• The DNS servers have been configured manually to something like OpenDNS, Google, or your ISP.
• The hosts have been infected with malware which is redirecting DNS to some bogus DNS servers.

Try using the nslookup command on the server and specifying your dnsmasq server as the third parameter.

nslookup ra.xsi 192.168.1.10

If this works, then check the DNS configuration on the host.