troubleshooting Question

Cisco NAT/ SMTP Configuration with Overload?

Avatar of aktharchowdhury
aktharchowdhuryFlag for United States of America asked on
RoutersCisco
13 Comments2 Solutions1607 ViewsLast Modified:
I have a new Cisco 2811 series router, and I need to make sure the email flows through on the right IP both inbound and outbound to ensure that email will not be rejected by domains doing reverse lookup.

So here's the basics:

fastethernet0/0 outside - 210.210.210.1
fastethernet0/1 inside - 10.0.1.1

mail inside - 10.0.1.50
mail public - 210.210.210.21

I've included what I've got in the router now.   My question / concern is - when email is sent from the inside to the outside internet - will it show as being from the router's .1 ethernet address instead of the .21 address?

Do I need to put an IP nat pool with an access list into place and what would that look like?

Also, should I configure the router for IP Overload?  Figuring 50-100 users on the internal network.
interface fastethernet0/0
description - INTERNET OUTSIDE
ip 210.210.210.1 255.255.255.224
ip nat outside
 
interface fastethernet0/1
description - INSIDE NETWORK
ip 10.0.1.1 255.255.255.0
ip nat inside
 
ip nat inside source static tcp 10.0.1.50 25 210.210.210.21 25 extendable
ASKER CERTIFIED SOLUTION
Jody Lemoine
Network Architect

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