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Forum Replies

  1. Hi Rene,

    in your post you have the config:

    ASA1(config)# object network SSH_SERVER
    ASA1(config-network-object)# host
    ASA1(config-network-object)# nat (DMZ,OUTSIDE) static interface service tcp 22 10022

    Which means that if you connect to port 10022 on the outside interface, the request in forwarded to port 80.
    BUT what happens the other way around? What if the internal host initiates the connection. It will be translated to the OUTSIDE IP, but will the port be changed as well? Is this translation only triggered if the specifi

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  2. Hello Florian

    These commands do the following:

    Any communication from the outside with a destination IP address of (the IP of the outside interface) and a port of 10022 will be translated and would reach the server at IP address on port 22. These commands are ONLY for traffic originating OUTSIDE with the specific destination IP and port pair.

    If decides to initiate a communication to a destination on the Internet, these commands have nothing to do with the behaviour of such an action. If you want servers on the DMZ to ac

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  3. Hello Florian

    According to Cisco, concerning the implementation of Network Object NAT:

    When a packet enters the adaptive security appliance, both the source and destination IP addresses and ports are checked against the network object NAT rules. The source and destination address in the packet can be translated by separate rules if separate matches are made. These rules are not tied to each other; different combinations of rules can be used depending on the traffic.

    Let’s take a look at your example:

    ASA1(config)# object network SSH_SERVER
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  4. Hello florian

    As mentioned in the Cisco quote, the command will function in both directions, however, the appropriate IP addresses and ports must be used in order for the transmission to match the NAT object and to successfully be translated.

    As for the (DMZ,OUTSIDE) portion of the command, it must have the following syntax:

    **nat** [(real_ifc,mapped_ifc)] …

    The real_ifc is the real interface, that is the interface pointing towards the server/device for which you are configuring static NAT. The mapped_ifc is the mapped interface, that is, the interface to whic

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  5. Hello Bruce

    Although it is true that the vast majority of NAT configurations are indeed nat (inside,outside), there are situations where the nat(outside,inside) scenario is useful. One such example is if you have a web server that is on the Internet that you want users on the inside of a network to access using an internal private address.

    This example can be seen in the following Cisco documentation on pages 2 to 4 in a section titled “NAT for Inside Hosts (Dynamic NAT) and NAT for an Outside Web Server (Static NAT)


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