Best way to capture packets to determine public IP address for port forwarding

[A4WanMan]

I am trying to direct traffic to a specific internal server using port forwarding and specific remote IPs.  My forwarding rule works as long as I have "any" in the allowed remote IPs.  If I enter the IP addresses (separated by commas) provided by the company, the internal server can not be accessed.  I'm thinking they gave me the wrong IP addresses. 

What's the best way to capture packets to see what the external IP address may be?

My port forwarding rule:

Uplink = Internet 1

Protocol = TCP

Public port = 150

LAN IP = internal server IP

Local port = 80

From the public side, I try to access the server such as:  http://{public ip address (wan 1)}:170/home.html

I have also tried a 1:1 NAT.  I get the same result.  I can access if I use "any", but not with the IP addresses given by the company.

[alemabrahao]

Your filter is wrong, you should filter by WAN and not by LAN. Think that the traffic will be entering through your WAN before reaching the LAN.

[alemabrahao · Accepted solution]

Something like this:

[A4WanMan]

I had the wrong senario:

forwarding rule:

Uplink = Internet 1

Protocol = TCP

Public port = 150

LAN IP = internal server IP

Local port = 80

Trying to access the server with:  http://{public ip address (wan 1)}:150/home.html

Access works if I don't restrict the rule to remote IP addresses.