Router – Recommendation for ADSL modem/router that supports multiple servers w. static IPs

In general: you should be able to configure your DHCP server to assign permanent leases based on MAC address to certain clients. I have DD-WRT set up on my WRT54G router to do just this - so certain machines on my network will always have the same IP. Hunt around for the options in your router's firmware, see if they're there :-)

DHCP will also handle DNS and gateway configuration - so you should just be able to enter these values on your DHCP server (you didn't specify which of your routers is handling it) and clients will pick it up automatically. Indeed, that's the primary function of DHCP!

Configuring port forwarding on a 60B is a several step process. First you need to create a Virtual IP for the interface (WAN2) and IP (I assume 10.1.10.10) you want to forward. Then you have to add a firewall rule allowing traffic from the virtual IP to the internal interface. Can you confirm you've already done both of these?

Also, you mention that your static IP (with Comcast) remained the same. If this is the IP of the modem, I'd expect it to be an external IP, ie not in the 10.xx subnet. Yet the WAN2 interface of your Fortigate has a 10.xx address. This suggests you've got a double-NAT setup.

If this is the case you can fix it in one of two ways:

1. Setup port forwarding/NAT on the modem (ie actually use double NAT - not nice)
2. Change the modem to 'bridge mode' and have the Fortigate get the external IP as its WAN2 IP (better).

Note that with 2 if your Comcast connection is eg ADSL w PPP, you'll need to configure the Fortigate to do do the PPPoE authentication.

Double-NAt would also explain why changing the router broke things - the old router had port forwarding/NAT configured, but the new one didn't.

Edit:

It really sounds like my guess at the double-NAT scenario is correct. The DSL modem connected to WAN1 is getting the external IP address, and is assigning a 10.1.10.xx address to the Fortigate's WAN1 interface via DHCP. If the old modem definitely didn't have port forwarding then it was probably in bridge mode.

If you can't access the newly added modem via your internal network, I recommend you take the following steps:

1. Connect to the modem directly with an ethernet cable to eg your laptop
2. From your laptop, access the modem's configuration web interface. If you cant reach it, reset the modem to factory defaults and point your web browser at its factory set IP. This is guaranteed to get you to a config page, but will wipe existing settings.
3. Within the interface, set the modem's IP address to something inside your internal network's IP range.
4. Access the modem at the new IP, configure all the ADSL related settings (not authentication, just lower layer settings like encapsulation, VPI/VCI etc. Get these from Comcast if you dont have them.
5. Set the modem to 'bridge' mode. This is the important step.
6. If your ADSL connection uses PPPoE authentication, access the Fortigate admin page, and under Network -> Interfaces -> WAN1, select PPPoE and enter your ADSL username and password.

If this all works, you'll see WAN1 on the fortigate get an external IP address.