Wireless Router and OSX Mail

[doop]

I purchased a Belkin Wireless G 802.11g Router for my eMac running OS 10.4.7. My ISP is Roadrunner, and I am connected via a Motorola SB4200 SURFboard cable modem. I use Safari for the web and the native Mail program for e-mail.

I installed the router in order to connect to my ISP with a Dell laptop with wireless internet that I was issued for my graduate work, so I could tap into the campus server from home.

I installed the router using the "easy install"; it's physically set up this way:

Cable ==> Modem ==> Router ==> Mac (via ethernet port)

It seemed to work perfectly at first. I could connect the laptop and surf the internet, and at the same time surf the internet with Safari on the Mac. The trouble is Mail on the Mac. When the Mac is connected through the router, Mail will not send or receive. When I try to check/receive e-mail, I get this message:

"The server error encountered was: The server "pop-server" cannot be contacted on port 110."

When I try to send e-mail, I get this message:

"The server "smtp-server" cannot be contacted on port 25."

I do not have a separate e-mail program running on the laptop, so I'm not sure if the same problem exists there. Again, I am connected to the internet, because I can surf the web on both the laptop and the Mac.

I have tried messing around with the settings on both the router and the network settings on the Mac. I saw no firewalls that appeared to be blocking anything on the Mac, and tried turning off the firewalls in the router. I also restored the router to factory settings and tried connecting with installing the software. Same result: can connect to the web, but can't work e-mail.

As soon as I unplug the router and plug the modem back into the Mac directly, Mail begins working fine again.

Any help would be greatly appreciated; I've searched and searched and found no answers online.

Thanks!

-- Doop