Single outside public - can I PAT out and NAT my SMTP server back in

[geraghtyconor]

Hello folks,

I have an ASA 5510, one public IP address on my outside interface, an internal email server and a private network.

I would like...

1: Users on my private network to be able to access the internet (PAT them to external outside address)

2: Email to be delivered to my MX (my single public IP address translated back to my internal email server.

i.e. can I share my single public IP address to serve translation in both directions (private users surfing the Internet (in-to-out) and an outside to inside NAT for email) ?

Email (MX) = 1.2.3.4

Public (outside) address = 1.2.3.4

Email server internal = 10.1.2.3

Internal private subnet for users = 10.0.0.0/8

[Ramraj Sivagnanam Sivajanam · Accepted solution]

Hi Bro

Yes, your requirements can be fulfilled with Cisco ASA.

static (inside,outside) tcp interface 110 tcp 10.1.2.3 110 netmask 255.255.255.255

static (inside,outside) tcp interface 25 tcp 10.1.2.3 25 netmask 255.255.255.255

static (inside,outside) tcp interface 25 tcp 10.1.2.3 143 netmask 255.255.255.255

global (outside) 1 interface

nat (inside) 1 10.0.0.0 255.0.0.0

access-list inside permit ip any any

access-list outside permit ip any any

access-group inside in interface inside

access-group outside in interface outside

For more Microsoft application's port numbers, please refer to this URL http://support.microsoft.com/kb/832017

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