Internet Box 3 - IP address of connected VPN clients on Synology

Ppmcl · Apr 18, 2021

Internet Box 3 - IP address of connected VPN clients on Synology

Hello,

I use the VPN server on the Internet Box 3 and then connect to the network with an L2TP/IPSec client, primarily to access the Synology NAS.

When checking the Synology logs, I noticed that the VPN client computer logs in with the external IP address of the Internet Box and does not receive an internal IP. Is it possible somehow to ensure that the VPN server of the Internet Box assigns an IP from the internal address pool to VPN clients? This would make configuring the Synology firewall much easier and more secure.

Thanks and greetings

Phil

DomiP · Apr 19, 2021

Are you sure you don’t get an IP? That sounds pretty unlikely…

hed · Apr 19, 2021

What kind of IP address does the client receive?

kaetho · Apr 19, 2021

hed

@pmcl

If a VPN connection is active on my IB3, it will be displayed to me like this with the IPs:

So I then see both IPs, but the local one is only displayed after the menu is opened.

Ppmcl · Apr 20, 2021

Thanks for the answers.

When I look at the clients with VPN in the IB3, I actually see an internal IP.

However, when I connect to my NAS (namely to the internal IP of the NAS), the Internet IP of the IB3 is still shown as the source in the log:

![](https://db3pap003files.storage.live.com/y4pNxDHAw2z4UCNcePZj2kIfSTcVasZa0kVo5p1-wLD4oBajwdvsGXKGL 1HzIHBQLjTvc6HRKpjqDxwSbmav4d-EVrMT8Q4MkMoqfVqaRK2tIW0-s74PFtL8ev5uT5bI3yTJyJI-wM0Ko0ZVy9949DaBRz6H-kl wLh99xhU-fHx9K-ZJZPbtfI1RHKyIZlzQN_m6Z-ri4lwqDdMnIUJLdp-w0BKRYDyJ41gV4spca_n2sY/Screenshot%202021-04-2 0%20at%2009.23.31.png?psid=1&width=864&height=52)

![](https://db3pap00 3files.storage.live.com/y4pNxDHAw2z4UCNcePZj2kIfSTcVasZa0kVo5p1-wLD4oBajwdvsGXKGL1H zIHBQLjTvc6HRKpjqDxwSbmav4d-EVrMT8Q4MkMoqfVqaRK2tIW0-s74PFtL8ev5uT5bI3yTJyJI-wM0Ko0 ZVy9949DaBRz6H-klwLh99xhU-fHx9K-ZJZPbtfI1RHKyIZlzQN_m6Z-ri4lwqDdMnIUJLdp-w0BKRYDyJ4 1gV4spca_n2sY/Screenshot%202021-04-20%20at%2009.23.31.png)![](https://db3pap003file s.storage.live.com/y4m0nwyjvvf1n3hAXPE7AZhSYZGhZG1g1ipgD2BQVHVw0BDbla3KQF6dwKJbz1fA Z2e0v9AM7KjNEkZU6ZKpp5mgbW_O-kpsi4Cw-3SoiMWGWWCFvZYFxZCQTNvMgfWM4aN3iktppNLzLZVUYPj OZlKGk1xTjJLWlckfRwKkks1fuiiUzpL7DyZF1hTxtuyuAJa?width=864&height=52&cropmode=none)

What could that be about?

Thank you

Phil

kaetho · Apr 20, 2021

Ok, at first glance it doesn’t make any sense. But I can’t judge whether this is a mistake or intentional.

Maybe @MichelB or @JonasB can say something about it?

Dr. Evil · Apr 20, 2021

If I were you, I would activate the Synology’s VPN server and pass through the ports on the IB3. Then your client will definitely receive a local IP number 10

Greetings

swissbeetle · Apr 21, 2021

Using the Nas VPN is probably not the safest solution!

POGO 1104 · Apr 21, 2021

@swissbeetle wrote:

Using the Nas VPN is probably not the safest solution!

Why not?

JonasB · Apr 21, 2021

Hello everyone

I discussed this with the team.

Public IP is assigned statically by the router to the VPN interface of the VPN client (smartphone, PC, etc.).
If the NAS is contacted via DynDNS or public IP, then the public IP of the VPN client is logged on the NAS (NAT hairpinning).

We’ll discuss this with other experts next week.

Ppmcl · Apr 21, 2021

Thank you very much for your answers.

I’m excited to see what comes out of your discussion!

Best regards

Phil

Herby · Apr 21, 2021

@pmcl

@pmcl wrote:

Thank you very much for your answers.

I’m excited to see what comes out of your discussion!

Many greetings

Phil

Me too…

JonasB · May 7, 2021

Hello everyone

Yesterday we were able to discuss the topic with all technical experts. We have come to the conclusion that this VPN usecase has a bug that we need to fix. As soon as I have a test version available, I will share it via PM for interested users.

Ppmcl · May 13, 2021

Thank you very much for the news!

Ppmcl · Jul 19, 2021

Hello @JonasB

I wanted to ask if there is any news on this matter yet?

Thank you and best regards

Philippe

JonasB · Jul 28, 2021

Hello @pmcl

Unfortunately, the developments have not yet been made and integrated. I hope that I will receive a firmware with the changes on August 19th.

LG Jonas

Ppmcl · Aug 23, 2021

Hello @JonasB

Thanks for the update, I’m looking forward to the new firmware.

JonasB · Aug 25, 2021

We discovered a problem during testing. I should be able to share the improved version by the end of this week.

JonasB · Aug 30, 2021

@pmcl

Testing is still ongoing, but no problems have been identified so far.

Here is the link to the new FW: https://t.mycloud.ch/c/zjrUBnFaMiXNt4wUpQ

Ppmcl · Nov 11, 2021

Hello @JonasB

Thanks for the link. Unfortunately I was very busy and it is no longer valid. Is this firmware automatically installed on the Internet Box? Otherwise I would be happy if you could make the FW available again.

Thanks and VG

Phil