problem of apache server with 2 interfaces

[yuenlok]

I've been fighting for this problem for a long time, any help would be appreciated
I have an Apache server has 2 interfaces qfe0 and hme0 connected to the front end and back end network respectively.

Front end interface: qfe0
IP: 142.124.187.78
network: 142.124.187.64
netmask: 255.255.255.224
broadcast: 142.124.187.95
router IP of frontend network: 142.124.187.65

Back end interface: hme0
IP: 142.124.187.12
network: 142.124.187.0
netmask: 255.255.255.192
broadcast: 142.124.187.63
router IP of backend network: 142.124.187.1

What happen is I can't do HTTP request from any machine in the backend network to the apache server's front end IP. (in the DNS, the server's domain name is configured to its front end IP, this makes sure all the HTTP request with the domain name will come from the front end)

I can telnet to the front end IP port 80, but wget always times out , and there's no any message logged in the apache access log.
wget stgznc01-01
--16:29:26--

http://stgznc01-01/

=> `index.html'
Resolving stgznc01-01... done.
Connecting to stgznc01-01[142.124.187.78]:80... connected.
HTTP request sent, awaiting response...
Read error (Connection timed out) in headers.
Retrying.

I snoop the apache server's interface and found the HTTP request actually come from the front end interface but the reply is sent to the back end interface. I assume this is because apache sees the client network is directly connected to it's backend interface and so it replis by back end. Is it caused the problem?

Is there any way I can force the apache server to reply the request with the same front end interface?

Thanks