DDNS update passing VPN subnet IP instead of my ISP IP

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What steps will reproduce the problem?

1. Attempting to use a VPN (e.g. Hide My Ass) and a DDNS service (e.g. No-IP)
2. Setup VPN details under Advanced Settings > WAN (L2TP, Enable NAT, Get MAN 
Auto., Entered account settings, xL2TPD, VPN IP: 9x.x.x.x)
3. Setup No-IP under Advanced settings > WAN > DDNS

What is the expected output? What do you see instead?

My public IP under checkip.dyndns.org is in the range for the VPN server I am 
connected to (e.g. 9x.x.x.x), however, my actual IPs are:

IPv4 address WAN: 10.x.x.x (private subnet, not sure if coming from ISP or VPN 
provider)
IPv4 address MAN: 8x.x.x.x (actual public IP of my router from ISP or VPN 
provider)

The 9x.x.x.x is being passed to NO-IP (or whatever DDNS provider), and instead 
I would like the MAN IP passed e.g. 8x.x.x.x

What version of the product are you using? On what operating system?

Using 3.0.3.6-061 on Windows 7 64bit

Please describe the problem as detailed as it's possible.

The problem is the IP being passed to NO-IP is not my actual IP, but my VPN 
subnet IP, I would like the MAN-IP passed if possible. Ideally the option to 
switch on a rule that says if IPv4 WAN address is private, pass of the MAN IP.

Original issue reported on code.google.com by james.ho...@gmail.com on 3 Jun 2013 at 6:40

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MAN - Metropolitan Area Network. Used for ISP local resources (IPoE 
connection). Usually 10.x.x.x or 172.16.x.x subnet.
WAN - under PPPoE/L2TP/PPTP connection always is VPN. 

Internet IPv4 under PPPoE/L2TP/PPTP always is VPN. DDNS used real Internet IPv4 
address from WAN, no MAN. 

MAN subnets 10.x.x.x and 172.16.x.x is not resolved from Internet.

Original comment by andy.pad...@gmail.com on 3 Jun 2013 at 7:10

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In that case I guess there is a problem as the IP address listed next to WAN IP 
is the 10.x.x.x address and the one next to the MAN IP is the real IP address 
(8x.x.x.x in this case). However, what is happening for me is my 'public' VPN 
IP (9x.x.x.x) is being posted to NO-IP.

I can send a screenshot to illustrate (I can't seem to attach one to a comment)

Original comment by james.ho...@gmail.com on 3 Jun 2013 at 8:28

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INADYN resolved you real IPv4 via http://checkip.dyndns.org, and output result 
in syslog. 

Original comment by andy.pad...@gmail.com on 4 Jun 2013 at 10:10

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Hi Andy, I understand the process, I was essentially making a request to see if 
it is possible to have the option to post my service provider IP address 
(8x.x.x.x) instead of the VPN assigned IP address (9x.x.x.x) to NO-IP. 

The VPN server I connect to (in this instance) is on the 9x.x.x.x range and 
then assigns be an IP address on that range, but for whatever reason traffic is 
not able to to come back the other way (when entering my NO-IP url into a 
browser for instance). 

Where as if NO-IP resolved back to my assigned ISP IP address (8x.x.x.x) it 
works fine (I tested this by manually entering into NO-IP via their admin page).

Original comment by james.ho...@gmail.com on 4 Jun 2013 at 10:04