Des is right; if you've configured your win9x box to obtain an IP address automatically, then the relevant settings should be automagically configured--you don't even need the host name, actually.
By default, you would be able to access your ISP's mail servers through the e-smith server--it doesn't do anything to block those ports. You'll need to try a few things to determine where the problem is.
First, from a command prompt on your Windoze box, type "ping mail.myisp.com" (or whatever the name of your ISP's mail server is). If this fails, try it from the command line on your e-smith box.
If you're able to ping the server from your client machine, go to start\run and enter "telnet mail.myisp.com 110" (again using the actual address of your ISP's pop server). If it connects, try to log in. Enter "user [your username]" and "pass [your password]" and see how it responds. Again, if this fails, try it from the command line on your e-smith box.
Good luck!