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  1. Junior Member
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    #1

    Default nat on frame relay

    Hello everyone! Can anyone help me configure NAT in frame relay network?
    i tried and it does not work .


    this is my configuration :

    here is picture of the network:

    http://s12.postimg.org/c7fij02d9/Capture.png

    if do not work for someone here is direct link:
    http://postimg.org/image/ggk8l65mh/

    #show running config

    Router left side :

    http://pastebin.com/afi2xGbZ


    Router right side :
    http://pastebin.com/7RS7nCYD

    here is the pkt file if someone want to download:

    http://www.filedropper.com/natframe-relay_1
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  3. Senior Member
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    #2
    Hi,
    in your scenario what is making a big confusion, in my point of view is EIGRP. when pc0 ping pc1 the ICMP packet is able to arrive to pc1 due to EIGRP but is not able to get back to pc0 because of the way NAT is configured.

    You dont need EIGRP at all. all you need to do if you want both pc's to ping each is to use STATIC NAT instead of DYNAMIC NAT (PAT). this way NAT will translate packets arriving to the inside global address to the inside local address.
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  4. Junior Member
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    #3
    Quote Originally Posted by Gngogh View Post
    Hi,
    in your scenario what is making a big confusion, in my point of view is EIGRP. when pc0 ping pc1 the ICMP packet is able to arrive to pc1 due to EIGRP but is not able to get back to pc0 because of the way NAT is configured.

    You dont need EIGRP at all. all you need to do if you want both pc's to ping each is to use STATIC NAT instead of DYNAMIC NAT (PAT). this way NAT will translate packets arriving to the inside global address to the inside local address.
    I used only two computers becuse i want to try nat on frame relay . on a real network it will be with 30+ computers at least .
    so i have to use overload nat/pat.
    Any way , why to cancal the eigrp? how the router will know to route ? even if they have nat .

    did you fix the problem and now it's working ? if it does , please upload the file
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  5. Senior Member
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    #4
    in your topology both routers r on the same network.. therefore u dont need routing protocol.. any device that is behind Nat cannot be pinged thats the behavior of Nat. you should not advertise private networks.. thats why they r called private. if u take out the EIGRP your topology will work fine. all the Nat configurations r correct.
    Last edited by Gngogh; 12-19-2014 at 02:52 PM.
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  6. Junior Member
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    #5
    Quote Originally Posted by Gngogh View Post
    in your topology both routers r on the same network.. therefore u dont need routing protocol.. any device that is behind Nat cannot be pinged thats the behavior of Nat. you should not advertise private networks.. thats why they r called private. if u take out the EIGRP your topology will work fine. all the Nat configurations r correct.
    So to have pings i have to use static nat ?
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  7. Senior Member
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    #6
    yes in your topology if you want the pc's to ping each other you have to use static nat. remember that this is not good practice in a production environment. Static NAT is used for servers that need to be available for external networks, never for workstations.
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  8. Junior Member
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    #7
    Quote Originally Posted by Gngogh View Post
    yes in your topology if you want the pc's to ping each other you have to use static nat. remember that this is not good practice in a production environment. Static NAT is used for servers that need to be available for external networks, never for workstations.
    Alright.

    btw , can you explain me why i have to use a subinterface to use nat on frame relay network ?
    the "serial 0/1/0.100 "
    and why i have to write point to point ?

    ty !
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  9. Senior Member
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    #8
    Subinterfaces have nothing to do with NAT. they are VC (virtual circuits) used in frame-relay networks. virtual circuits are like virtual connections that exist within the same physical connection. similar to a VPN. You can configure frame-relay as point-to-point or as by default point-to-multipoint.
    you have to declare point-to-point on a subinterface otherwise you cannot configure a subinterface.
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