DNS / Squid / iptables / proxy / browsing error
 

I am trying to get Squid configured as a transparent proxy in order to use SquidGuard for a basic filter. For some sites, it works great. However, other sites appear to open the wrong page.

For example, I can browse to Google, Yahoo, and Technorati without problems. However, when I try to go to GMail, I get the Google web search screen. The same thing happens with Blogger – I get the Google web search screen. When I type in the IP address for gmail (obtained using the dig command), I still get the Google web search screen. This is occurring when I have the browser configured to Squid as a proxy with port 3128 as well as when I have the browser configured to connect directly (port 80).

The majority of our Internet traffic goes thru our BorderManager server on port 8080. When the browser is set to connect to this filter, everything works as expected.

I’ve checked the resolve.conf file and verified that the nameservers listed on the Linux box are the same as the ones on the BorderManager box. I’ve used dig on the Linux box and can get what appears to be the correct information for gmail. I get similar but abbreviated results on my Windows workstation using nslookup.

The Linux box is running Red Hat release 9. It is configured with 3 nics.
Eth0 private
Eth1 public
Eth2 DMZ

The BorderManager box is running Novell Netware 6. It is configured with 2 nics: private and DMZ.

When the browser is set to use the BM proxy (port 8080), the traffic goes from the workstation to the proxy on the local network. The proxy connects to the Linux firewall via the DMZ and traffic then proceeds to the public side (Internet) from the Linux firewall.

When the browser is set to use Squid, the traffic goes from the workstation to the Linux firewall on the private side. It then proceeds to the public side (Internet) from the Linux firewall.

Being a newb, this problem is way above my capabilities. Any suggestions would be appreciated.