PPPoE, A1 Telekom, IP address on WAN different as in CheckIP

juergenbrandstaetter

I have a A1 Telekom ASDL (copper) and operate my Telekom Modem as "Single User".

Behind is a Pfsense, and I configured the WAN interface correctly with PPPoE and my credentials and Internet works perfect with full speed.

Here is the problem:

The WAN interface on Pfsense shows a different IP address as the one which is registered in my DynDNS by the "CheckIP" function of Pfsense.

Also my packets arrive at another place with this other IP address. I checked that by dialing-in into another network and checked the source IP. It's the same as the DynDNS says.

So, actually, this is all as it should be.

BUT, this becomes a problem, if I want to dial into my network, where I have configured an IPSec/L2TP access point.

My request from outside does not arrive at my PFsense, neither when I direct it to the IP address shown at the WAN nor when I direct it to the one in DynDNS (which I expected that it works).

Why is that so? Is a configuration missing?

I also tried to put my WAN on a VLAN with VLAN tag "2", which I read that A1 Telekom is using -> if I do that, the Internet connection does not work at all, but I am not sure, if I configure that correctly.

The same configuration of my PFsense here has worked on another site with Magenta Provider. The only difference to there is, that the Magenta Provider required DHCP at the WAN interface, not PPPoE and the IP address on the WAN interface was the same as the "CheckIP" function put into my DynDNS.

Any help appreciated.

viragomann

@juergenbrandstaetter said in PPPoE, A1 Telekom, IP address on WAN different as in CheckIP:

The WAN interface on Pfsense shows a different IP address as the one which is registered in my DynDNS by the "CheckIP" function of Pfsense.

Which one? Maybe a CG-NAT?

juergenbrandstaetter

@viragomann I don't know what this is, but this is shown in the status of the WAN interface:

IPv4 Address: 100.xxx.xxx.xxx
Subnet mask IPv4: 255.255.255.255
Gateway IPv4: 100.xxx.xxx.xxx

And the one shown in DynDNS is 217.xxx.xxx.xxx

viragomann

@juergenbrandstaetter
Yes, it's a CG-NAT.

That's a kind of private IP, which is natted at ISP site to a real public IP. But this works only for outbound.

There is no way to access it from outside. You have to get a pubic IP from your ISP.

juergenbrandstaetter

@viragomann Many thanks!!

That makes sense, although this is really bad :(

With your keyword I found an article in the A1 forum. There they indicated that the A1 support could fix that somehow for the guy.

The only thing I need is that they forward the ports, well, I will chat with them, let's keep fingers crossed.

Thanks again!