My setup:

DMZ FTP server - 192.168.3.x (CentOS)

Smoothwall Firewall (in the middle with ports open between FTP and NAS)

LAN NAS - 192.168.0.x (Buffalo Linkstation)

I'm trying to setup my rsync backup that use to exist when my server was inside my LAN. Now that my server is on the DMZ, it can not communicate with my NAS on the LAN. My smoothwall firewall has everything open in the middle for the SMB sharing using ports 136:139 & 445 all TCP.

I think the issue is with the iptables on the server. This is an example of the opening I made for the ports on the FTP server on the DMZ:

iptables -A INPUT -s 192.168.100.50 -p tcp --dport 136:139 -j ACCEPT

It would seem that I still can not see the NAS on my LAN. What am I missing? I imagine it's a static route to the LAN. Not sure how to write it. Any help would be appreciated.

I think the problem is that they are on 2 different networks (192.168.3.0 and 192.168.0.0). Make sure you have the correct gateway specified in the route. Also, I believe that SMB is non-routable, unless you use something like a VPN to connect to the other network. I'm not too familiar with SmoothFirewall so maybe it has this feature?

I forget how to use the route command off the top of my head, but you can look it up. Also make sure the rsync ports are open for rsync.

I would probably recommend using SSH to rsync between these two computers to the different network.

Not sure why you cannot see your NAS on your LAN. Have you tried pinging it?

I'm pretty sure it was saying that the host is not reachable when i try to ping from DMZ to LAN. For some reason I think i have to put a static route to/from each network in the iptables so my DMZ server knows how to communicate with the NAS on my LAN. I haven't even got to the rsync part yet. hahaha. First I have to able to connect from the DMZ server to my LAN NAS.

Just temporarily disable iptables and start from there, get everything working, then start setting iptable rules.

I should have realized that if you only enabled ports 136:139 and 445, then all other packets will be dropped, including ping, unless you enable icmp (I think).

Once I've done that I get connection timeouts on port 445 or 139. Could be UDP? I have TCP ports specified. Maybe I need UDP as well.