Routing issue 14.04

I have a 14.04 server set up to run OwnCloud. Everything was working for six months up until yesterday.

We have two sub-nets involved:

192.168.20.0/24 is our Corporate network.
192.168.0.0/23 is our Guest network. (OwnCloud server is here for student access)

192.168.1.2 is our firewall. eth0 is disabled and not used.

Problem is from the OwnCloud server. I caot resolve any DNS names. If I use IP's it goes through except on our Corp network. Caot see it at all. Here's some info.

/etc/network/interfaces

auto eth1
iface eth1 inet static
address 192.168.1.28
netmask 255.255.254.0
gateway 192.168.1.2
nameservers 192.168.1.2, 192.168.20.9
broadcast 192.168.0.255
post-up route add -net 0.0.0.0 netmask 0.0.0.0 gw 192.168.1.2 eth1
post-up route add -net 192.168.0.0 netmask 255.255.254.0 gw 192.168.1.2 eth1
post-up route add -net 192.168.20.0 netmask 255.255.255.0 gw 192.168.1.2 eth1

>route -n

Keal IP Routing table
Destination       Gateway        Genmask        Flags Metric Ref    Use    Iface
0.0.0.0            192.168.1.2    0.0.0.0           UG    0       0        0      eth1
192.168.0.0       0.0.0.0        255.255.254.0   U     1       0        0      eth1

From the OwnCloud server, if I ping the guest network I see the nodes. If I ping 8.8.8.8, I get a retu. Ping google.com, nothing. Ping DNS server IP on Corp and nothing. The staff and instructors caot access the OwnCloud server from Corp to upload materials.

This was working perfectly until yesterday. My guys tell me no one has changed anything, but I'm not sure. Do you notice any reason why this would not work? I've been staring at this for four hours and I'm mystified.

Cheers.