Pix behind Cable Modem/DSL and hosting Mail

[pmonfile]

If I have a cable modem/DSL box that has a single static on the outside of it, and it does NAT and DHCP, can I host an SMTP server inside a Pix?

Example, outside device is at 65.102.241.209/29. It delivers 192.168.1.0/24 DHCP Addresses. The Pix picks up 192.168.1.1/24 as its outside address. It in turn gives 10.0.0.0/24 addresses internally, and the SMTP host is at 10.0.0.1.

How would I set the MX record to point to 65.102.241.209 and have the Pix deliver port 25 traffic to 10.0.0.1?

Do you remove NAT on the Pix and use the 192.168.1.0 subnet on both sides?

I get the feeling this can be done with version 6.2(2), but I am having a mental block on how.

Thanks for all assistance in advance.

[mostiguy]

If the cable/dsl box does nat, why are you using a pix? You need a legitimate ip address on the outside of the pix. If you can achieve that:

set up the mx record to point to a host. have a record for that host to be 65.x.x.x.

on the pix:

global (outside) 1 interface

static (inside, outside) tcp interface 25 10.0.0.1 25 netmask 255.255.255.255

write an access list that allows smtp from everyone:

... permit tcp any any smtp

apply it to the outside interface.

done.