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New Member

Problems with NATing


in our company we have a Cisco 1802 installed and need to use NAT.

During a configuration change for one of our customers we needed to change the inside and outside NAT interfaces.

The configuration worked fine until we have to make a change for our new video communication device.

Here are some snippets of the router configuration:

interface fast 0 (connected to the internet)

ip address

ip nat inside (we can't change this, because it's needed for another config)

interface vlan1 (local network)

ip adress

ip nat outside

The video communication device has the address and should be externaly avaible via so i did the following:

ip nat outside source static

The default gateway of the VCD is

After setting the NAT entry becomes ping-able from the outside but the device isn't reachable by a web browser or another VCD.

Does someone has any ideas?

with kind regards

I. Jacob

Everyone's tags (2)
Cisco Employee

Re: Problems with NATing

Hi Jacob,

If you do:

ip nat outside source static

You actually create a rule to tranform the destination IP address of outgoing (in->out) from to -or- translate the source IP address of incoming packets (out->in) the same way.
When you ping I belive it's the router that reply as the packet is being "received" on the router by adding that nat rule. You can confirm by doing "debug ip icmp" on the router if you want. Since no http server is enbaled on the router, you can't access this ip with a browser.
So, what you need here is a static rule to translate the destination ip address of an incoming packet (out->in) from to -or- the source ip address of an outgoing packet (in->out) to to Which the definition of a static inside rule:

ip nat inside source static
Can you try that and let me know if this worked?

New Member

Re: Problems with NATing


thanks for your reply but i solved the problem meanwhile.

i replaced the current entry with this one

ip nat outside source static add-route

and it worked for me.