Comments on: NAT port Fowarding in packet tracer

By: sixball

sixball — Tue, 01 Nov 2011 18:18:45 +0000

A list of really quick issues with the PKT you provided:

- Both Servers have the exact same IP address
– “Internet” server: 195.10.10.5 /24, gw 195.10.10.1
– “Data” server: 195.10.10.5 /24, gw [u]195.10.1.1[/u]

- The gateway of “Data” server is 195.10.1.1, which is Fa0/1 on “Router1″, which is in a “down” state (the only cable from Switch3 goes into Fa0/0 on Router1)

- Fa0/0.10 on Router 1 AND Fa0/0 on “ISP” router have the exact same IP address
– Fa0/0.10 (Router1) = 195.10.10.1 /24
– Fa0/0 (ISP) = 195.10.10.1 /24

- The “Internet” server does not have a DNS server configured (not even to itself)

- On the “Internet” server, the ONLY DNS entry – “A Record” for http://www.isp.com – points to 200.10.10.1 – which is Interface Serial0/0 on the 2620XM “Internet Router”

- Pings from “Internet” server to PC4 (195.10.20.22) give “Destination host unreachable”

- Pings most likely failed due to routing configuration issues. In your original post, you have the following from the ISP router:
router eigrp 1
network 200.20.10.0
–> (Missing network of Interface Fa0/0) <–
auto-summary
[b]( interface FastEthernet0/0, ip address 195.10.10.1 255.255.255.0 )[/b]

Just on a 30-minute once-over, seems you have a few more design issues besides forwarding of DNS to your servers…

By: bitbytetw

bitbytetw — Sat, 29 Oct 2011 16:09:30 +0000

also here is a link to download the .pkt file if you wish to take a look at the network first hand

By: bitbytetw

bitbytetw — Sat, 29 Oct 2011 15:38:43 +0000

well you see that’s the problem, this ISP router is connected to a dns server through a 2950-24. its all networked up and working and the dns server can ping all the way to the 3rd router in my packet tracer model. but as soon as i send dns traffic it’s dropped ? if you would like i can try upload my packet trace model.

but as you can see in the show run, the port forwards are directing traffic to the dns server at 195.10.10.5. when i go into the packet analysis it goes to layer 4 searches for a service running finds no service running on the ports when there clearly is with the rules ive made and drops the packet.