[Dnsmasq-discuss] LAN taken down by Ubuntu upgrade - can't see problem

[adam.ant at cyberspaceroad.com]

I upgraded the OS on my gateway machine which runs dnsmasq serving dhcp
and dns to the lan, and now the machines on my lan can't get an ip
address.

With ubuntu, I run dnsmasq in a stand-alone mode, in contrast to the
ubuntu 'way' where the default installation installs dnsmasq and sets it
up for optimal desktop networking - which doesn't work well for a gateway
machine.

My lan is on eth1, my modem is on eth0. Eth1 is assigned 192.168.0.3 by
/etc/network/interfaces, and this is what dnsmasq is configured to run on.

I hope you can give me a hint where to look next because as far as I am
aware, the only thing that changed was the ubuntu upgrade and I'm not
getting any help from the forum there, and my investigations with my
limited experience has run into the sand.

Here's the config & set-up:

my dnsmasq.conf:

adam at gondor:~$ decomment.sh /etc/dnsmasq.conf
domain-needed
bogus-priv
filterwin2k
server=/localdomain/127.0.0.1
local=/localdomain/
interface=eth1
bind-interfaces
expand-hosts
domain=localdomain
dhcp-range=192.168.0.4,192.168.0.250,12h
dhcp-option=option:router,192.168.0.3
dhcp-option=option:mtu,1492
log-dhcp


This is my /etc/resolv.conf:

adam at gondor:~$ cat /etc/resolv.conf
domain localdomain
search localdomain
nameserver 127.0.0.1
nameserver 213.120.234.6
nameserver 194.74.65.68
nameserver 208.67.222.222
nameserver 208.67.220.220
nameserver 8.8.8.8
nameserver 8.8.4.4


my /etc/hosts

adam at gondor:~$ cat /etc/hosts
127.0.0.1	localhost gondor gondor.localdomain
192.168.0.3	gondor.localdomain

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters


This is the output I get with netstat:


adam at gondor:~$ sudo netstat -nl46p|grep dnsmasq
tcp        0      0 127.0.0.1:53            0.0.0.0:*               LISTEN
     1203/dnsmasq
tcp        0      0 192.168.0.3:53          0.0.0.0:*               LISTEN
     1203/dnsmasq
tcp6       0      0 ::1:53                  :::*                    LISTEN
     1203/dnsmasq
tcp6       0      0 fe80::2a37:37ff:fe03:53 :::*                    LISTEN
     1203/dnsmasq
udp        0      0 127.0.0.1:53            0.0.0.0:*                     
     1203/dnsmasq
udp        0      0 192.168.0.3:53          0.0.0.0:*                     
     1203/dnsmasq
udp        0      0 0.0.0.0:67              0.0.0.0:*                     
     1203/dnsmasq
udp6       0      0 ::1:53                  :::*                          
     1203/dnsmasq
udp6       0      0 fe80::2a37:37ff:fe03:53 :::*                          
     1203/dnsmasq
adam at gondor:~$


but this is what I get from nmap when looking at the internal IP address
of the gateway's 2nd nic:


adam at gondor:~$ nmap 192.168.0.3

Starting Nmap 6.00 ( http://nmap.org ) at 2013-06-29 16:42 BST
Nmap scan report for gondor.localdomain (192.168.0.3)
Host is up (0.00049s latency).
Not shown: 994 closed ports
PORT     STATE SERVICE
21/tcp   open  ftp
22/tcp   open  ssh
53/tcp   open  domain
80/tcp   open  http
3689/tcp open  rendezvous
8080/tcp open  http-proxy

Nmap done: 1 IP address (1 host up) scanned in 0.13 seconds
adam at gondor:~$


and this for UDP because DHCP is served via UDP:

adam at gondor:~$ sudo nmap -sU 192.168.0.3

Starting Nmap 6.00 ( http://nmap.org ) at 2013-06-29 16:53 BST
Nmap scan report for gondor.localdomain (192.168.0.3)
Host is up (0.000012s latency).
Not shown: 997 closed ports
PORT     STATE         SERVICE
53/udp   open          domain
68/udp   open|filtered dhcpc
5353/udp open|filtered zeroconf

Nmap done: 1 IP address (1 host up) scanned in 1.25 seconds