Cannot access to Local Resource after VPN client connection established with VPN Server

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steven0606
Posts: 7
Joined: Thu Dec 26, 2019 5:08 pm

Cannot access to Local Resource after VPN client connection established with VPN Server

Post by steven0606 » Thu Dec 26, 2019 5:13 pm

Hello SoftEther team,
I had issue after VPN client connection established with VPN Server. VPN client cannot connect to local resource at physical site that VPN client reside.
Eg:
+ Physical site A:
+ Web A
+ VPN client
+ Physical site B:
+ Web B
+ VPN Server
After VPN client established VPN connection. VPN client cannot connect to Web A.
All VMs in Azure. Pls help me to resolve it.

sky59
Posts: 335
Joined: Tue Sep 11, 2018 5:58 pm

Re: Cannot access to Local Resource after VPN client connection established with VPN Server

Post by sky59 » Thu Dec 26, 2019 5:47 pm

What is web A and B? Browsers?

steven0606
Posts: 7
Joined: Thu Dec 26, 2019 5:08 pm

Re: Cannot access to Local Resource after VPN client connection established with VPN Server

Post by steven0606 » Fri Dec 27, 2019 1:58 am

Hi Team,
Thank for quick response. It is Web Server.

sky59
Posts: 335
Joined: Tue Sep 11, 2018 5:58 pm

Re: Cannot access to Local Resource after VPN client connection established with VPN Server

Post by sky59 » Fri Dec 27, 2019 3:39 am

This is normal and reason to use vpn.

What you need in your case you must change ip route table according to your non standard needs

ethanolson
Posts: 36
Joined: Mon Dec 02, 2019 6:29 am

Re: Cannot access to Local Resource after VPN client connection established with VPN Server

Post by ethanolson » Fri Dec 27, 2019 5:00 am

You need to not have the SE client change the routing tables (there's a checkbox for it), otherwise the entire traffic goes over the VPN connection and the far end doesn't know how to get back to your LAN subnet, so it then sends your traffic requests out to the internet. If you need a custom routing table, there are a few things that can be done, such as defining it in an OpenVPN client config and using OpenVPN to make the VPN connection, or SoftEther's SecureNAT static routing table push to the client. That will establish where certain subnets are accessed (nexthop/gateway).

steven0606
Posts: 7
Joined: Thu Dec 26, 2019 5:08 pm

Re: Cannot access to Local Resource after VPN client connection established with VPN Server

Post by steven0606 » Fri Dec 27, 2019 8:26 am

Thanks @Sky59 and @ethanolson. I want VPN client to connect with Local Resource after establishing VPN connection. Can you send me the detail document to configure? Im newbie on these.
Warmest regards,

steven0606
Posts: 7
Joined: Thu Dec 26, 2019 5:08 pm

Re: Cannot access to Local Resource after VPN client connection established with VPN Server

Post by steven0606 » Fri Dec 27, 2019 12:20 pm

Hi @Sky59 and @ethanolson,
It worked well. Thank you so much. I did:
***On VPN client
- No change anything.
***On SoftEther VPN Server
- Configure static routing from SoftEther's SecureNAT to push to VPN client.

Warmest regards,
Steven

sky59
Posts: 335
Joined: Tue Sep 11, 2018 5:58 pm

Re: Cannot access to Local Resource after VPN client connection established with VPN Server

Post by sky59 » Fri Dec 27, 2019 4:51 pm

I am at this moment on holidays in Phuket Thailand.
So if I remember correctly using securenat is not stable. I think
also warning window with this message is coming out when selecting
securenat. And I did have a problem so I could not use it. It was dropping
connection within minutes sometimes seconds.
For me the only option was to adapt ip route table

steven0606
Posts: 7
Joined: Thu Dec 26, 2019 5:08 pm

Re: Cannot access to Local Resource after VPN client connection established with VPN Server

Post by steven0606 » Sat Dec 28, 2019 6:57 am

Hi @Sky59,
Thank you so much. You mean, we should modify Routing table at Client site? If so, lets me do testing on this.

sky59
Posts: 335
Joined: Tue Sep 11, 2018 5:58 pm

Re: Cannot access to Local Resource after VPN client connection established with VPN Server

Post by sky59 » Sat Dec 28, 2019 4:07 pm

I would say yes.

I needed opposite situation to force all trafic to vpn.
Though i do not have exactly your experience it must be possible to do.

I just guess that subnet where was client before vpn client started must remain to be directed to original gateway

I guess now at the client the 0.0.0.0 is probably redirected to vpn server ip address

ethanolson
Posts: 36
Joined: Mon Dec 02, 2019 6:29 am

Re: Cannot access to Local Resource after VPN client connection established with VPN Server

Post by ethanolson » Sat Dec 28, 2019 8:18 pm

I can speak for Windows clients. If the local subnet range is unique then routing all traffic through the VPN will still allow for the local subnet to be accessed locally. It works that way because of routing metrics. Since the subnet addresses can't be found through the primary gateway, the client moves down the metric ladder until it can access the address. The bigger issue is DNS.

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