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NAT Port Forwarding RDP Issue

matthewjwilson
Level 1
Level 1

I have a 3825 set up that uses port address translation to forward incoming port 22 on my "external" IP address 10.10.1.110 to port 22 on the "internal" IP address 10.1.0.1. I am in fact able to SSH to 10.10.1.110 and get connected to the appropriate device.

When I run the "show ip nat translation" command, the following correct output is shown:

Router#show ip nat tr
Pro Inside global      Inside local       Outside local      Outside global
tcp 10.10.1.110:22     10.1.0.1:22        10.7.0.6:13724     10.7.0.6:13724
tcp 10.10.1.110:22     10.1.0.1:22        10.7.0.6:13772     10.7.0.6:13772

I am trying to do the same thing with RDP so that I can access a Windows machine. There is no firewall on the network or running on the Windows machine, so I know that RDP is not blocked anywhere. I can RDP to the machine from within the same network, and when I try to RDP to the "external" 10.10.1.110 address, the following shows up in the NAT translation table:

Router#show ip nat tr
Pro Inside global      Inside local       Outside local      Outside global
tcp 10.10.1.110:22     10.1.0.1:22        10.7.0.6:13724     10.7.0.6:13724
tcp 10.10.1.110:22     10.1.0.1:22        10.7.0.6:13772     10.7.0.6:13772

tcp 10.10.1.110:3389   192.168.99.2:3389  10.7.0.6:13861     10.7.0.6:13861

The translation shows up in the NAT translation table, but the RDP session never connects. Here are the NAT configuration commands I am using (I omitted the "ip nat inside/outside" commands):


ip nat inside source static tcp 10.1.0.1 22 10.10.1.110 22 extendable
ip nat inside source static tcp 192.168.99.2 3389 10.10.1.110 3389 extendable

Does anyone have any idea why SSH works with its NAT translation but RDP does not?

1 Accepted Solution

Accepted Solutions

lgijssel
Level 9
Level 9

Your nat entries look ok so there is no problem inbound,

However, the RDP session connects to a different machine.

It is likely that this machine does not have a route back to the outside.

Please check the routing between network 192.168.99.0 and 10.7.0.0

regards,

Leo

View solution in original post

2 Replies 2

lgijssel
Level 9
Level 9

Your nat entries look ok so there is no problem inbound,

However, the RDP session connects to a different machine.

It is likely that this machine does not have a route back to the outside.

Please check the routing between network 192.168.99.0 and 10.7.0.0

regards,

Leo

Leo, thank you so much! It's always something simple that you just overlook... What had happened was that I forgot the "default-originate" command under my BGP configuration, so no other router had a default route!

Thanks again.

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