SMC Comcast Business Router Configuration

There are a number of other posts with similar questions, but none that I found were able to help me.

When you get a business line from Comcast they give you an SMC router/firewall/modem. Before switching to Comcast business, we had a SonicWall firewall configured and working perfectly for our previous ISP. It allowed inbound terminal services to our terminal services server and OWA (http/https) connections to our exchange server.

Now that I have to place this SMC router in front of the firewall, I'm in a situation where getting the double NAT'ed firewalls working is not as simple as I had hoped.

I know the setup below is wrong because although I have internet access from behind the SonicWall, I can't get in from the outside using services that previously worked (OWA and terminal services).

Comcast wrote down two IPs on the work order:

So this is my setup on the SonicWall:
WAN: NAT-Enabled Static IP:


Static IP Block
"Firewall for True Static IP Subnet Only" disabled
"Gateway Smart Packet Detection" disabled
"Static Routing" disabled
"Port Forwarding" disabled
"1 to 1 NAT" disabled is in the DMZ (I was trying to achieve a "bridge-like" mode even though this device doesn't have a bridge mode)

When I check my public IP from behind the SonicWall, it's currently

What do I need to change for this to work properly?

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nappy_dThere are a 1000 ways to skin the technology cat.Commented:
Did Comcast provide you with any public IPs for usage?

Does the SMC device have any ethernet ports on it?  If so, try configuring your sonicwall with one of the public IPs and connect it to the LAN port on the SMC box.

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DVation191Author Commented:
Well the smc gateway has an ip of .206, I;m supposed to be using the .205 address, as we've paid for a static IP.

The SMC does have ethernet ports on it - 4 to be exact. If I configure the SonicWall's WAN IP as the .205 IP, what do I use as the gateway?
nappy_dThere are a 1000 ways to skin the technology cat.Commented:
Use the .206 as the gateway.  This gateway is not for the SMC device but your ISP's gateway for the internet.

Connect your Sonicwall unit to the etheret port located on the SMC device.
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DVation191Author Commented:
Thank you!
One major Issue:
The part that your sonicWall has a WAN ip of and a Gateway of is wrong. You can never have that. Meaning the Gateway and IP of the device have to be on the same network.
Issue Number 2: you mentioned that: is in the DMZ (I was trying to achieve a "bridge-like" mode even though this device doesn't have a bridge mode) and 1 to 1 NAT" disabled
So what is your internal IP address of sonic wall? How does it communicate with the gateway you provided? Like I said they have to be on the same network for them to talk to each other. there needs to be some sort of a translation or NATing. (your issue number 2)
I just gave you list of things that are wrong but I have not provided any solution. So answer these questions so I can give you some more help. Which device acts as the DHCP server? Which device does the NATing? May be you can disable the NAT on your SMC device and make it act like a layer 2 bridge (roughly).
Let me know
DVation191Author Commented:
Setting the WAN IP on the firewall to .205 and using .206 as the gateway (the smc device), I was able to get an internet connection working with .205 as my public IP. My internal addresses behind the firewall are using 192.168.40.x, but that doesn't seem relevant. Everything seems to be working now.
So what is it that you are looking for? What are you trying to fix that doesn't work?
DVation191Author Commented:
Everything works now - that's why I closed the question and awarded points =)
Oh, damn LOL
I didn't see that you closed it. Well, good luck
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