Softether Bridge and Client on same server - L2TP stops working

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tstalzer
Posts: 3
Joined: Wed May 12, 2021 6:11 pm

Softether Bridge and Client on same server - L2TP stops working

Post by tstalzer » Tue Jun 18, 2024 1:12 pm

Hello
We have a rather complex installation which works fine except for one thing.

On a windows server, we have a Softether bridge to connect to multiple client networks. On the same server, I have a Client active to grant access from this server to a remote network. Everything works fine and was quite straight forward to setup.

However, We have some clients that connect via L2TP to the bridge. As soon as the local Softether Client is activated, the L2TP clients can no longer connect.

I have a feeling it has something to do with opening the L2TP ports on the newly active VPN virtual network adapter from Softether client. Do you have an idea or recomendation on how to set this up?
Thank you

--Thomas

solo
Posts: 1387
Joined: Sun Feb 14, 2021 10:31 am

Re: Softether Bridge and Client on same server - L2TP stops working

Post by solo » Tue Jun 18, 2024 2:29 pm

On the SE client set "No Adjustments of Routing Table" option. If ineffective, un-set it and post as code the output of "netstat -r" when the client is connected.

tstalzer
Posts: 3
Joined: Wed May 12, 2021 6:11 pm

Re: Softether Bridge and Client on same server - L2TP stops working

Post by tstalzer » Tue Jun 18, 2024 4:39 pm

Hello Solo

unfortunately setting "No Adjustments of Routing Table" did not work.

Here is the result of "netstat -r" first with the SE Client connected

Code: Select all

===========================================================================
Interface List
 13...5e 95 1f ac da 7b ......VPN Client Adapter - VPN
 14...00 1c 42 3f 70 aa ......Virtuozzo VirtIO Ethernet Adapter
  1...........................Software Loopback Interface 1
 12...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter
 27...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #2
===========================================================================

IPv4 Route Table
===========================================================================
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0      169.254.0.1     5.175.24.253      6
          0.0.0.0          0.0.0.0    192.168.130.1   192.168.130.27      2
     5.175.24.253  255.255.255.255         On-link      5.175.24.253    261
   80.237.128.145  255.255.255.255      169.254.0.1     5.175.24.253      6
        127.0.0.0        255.0.0.0         On-link         127.0.0.1    306
        127.0.0.1  255.255.255.255         On-link         127.0.0.1    306
  127.255.255.255  255.255.255.255         On-link         127.0.0.1    306
    130.158.6.115  255.255.255.255      169.254.0.1     5.175.24.253      6
    192.168.130.0    255.255.255.0         On-link    192.168.130.27    257
   192.168.130.27  255.255.255.255         On-link    192.168.130.27    257
  192.168.130.255  255.255.255.255         On-link    192.168.130.27    257
        224.0.0.0        240.0.0.0         On-link         127.0.0.1    306
        224.0.0.0        240.0.0.0         On-link      5.175.24.253    261
        224.0.0.0        240.0.0.0         On-link    192.168.130.27    257
  255.255.255.255  255.255.255.255         On-link         127.0.0.1    306
  255.255.255.255  255.255.255.255         On-link      5.175.24.253    261
  255.255.255.255  255.255.255.255         On-link    192.168.130.27    257
===========================================================================
Persistent Routes:
  Network Address          Netmask  Gateway Address  Metric
          0.0.0.0          0.0.0.0      169.254.0.1       1
===========================================================================

IPv6 Route Table
===========================================================================
Active Routes:
 If Metric Network Destination      Gateway
 14    261 ::/0                     fe80::ffff:1:1
  1    306 ::1/128                  On-link
 14    261 2a01:488:66:1000:5af:18fd:0:1/128
                                    On-link
 14    261 fe80::/64                On-link
 13    266 fe80::/64                On-link
 14    261 fe80::b9e9:56bc:14aa:d561/128
                                    On-link
 13    266 fe80::dd41:1e16:8d5:77da/128
                                    On-link
  1    306 ff00::/8                 On-link
 14    261 ff00::/8                 On-link
 13    266 ff00::/8                 On-link
===========================================================================
Persistent Routes:
 If Metric Network Destination      Gateway
  0 4294967295 ::/0                     fe80::ffff:1:1
===========================================================================
Now with the SE Client disconnected

Code: Select all

===========================================================================
Interface List
 13...5e 95 1f ac da 7b ......VPN Client Adapter - VPN
 14...00 1c 42 3f 70 aa ......Virtuozzo VirtIO Ethernet Adapter
  1...........................Software Loopback Interface 1
 12...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter
===========================================================================

IPv4 Route Table
===========================================================================
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0      169.254.0.1     5.175.24.253      6
     5.175.24.253  255.255.255.255         On-link      5.175.24.253    261
        127.0.0.0        255.0.0.0         On-link         127.0.0.1    306
        127.0.0.1  255.255.255.255         On-link         127.0.0.1    306
  127.255.255.255  255.255.255.255         On-link         127.0.0.1    306
        224.0.0.0        240.0.0.0         On-link         127.0.0.1    306
        224.0.0.0        240.0.0.0         On-link      5.175.24.253    261
  255.255.255.255  255.255.255.255         On-link         127.0.0.1    306
  255.255.255.255  255.255.255.255         On-link      5.175.24.253    261
===========================================================================
Persistent Routes:
  Network Address          Netmask  Gateway Address  Metric
          0.0.0.0          0.0.0.0      169.254.0.1       1
===========================================================================

IPv6 Route Table
===========================================================================
Active Routes:
 If Metric Network Destination      Gateway
 14    261 ::/0                     fe80::ffff:1:1
  1    306 ::1/128                  On-link
 14    261 2a01:488:66:1000:5af:18fd:0:1/128
                                    On-link
 14    261 fe80::/64                On-link
 14    261 fe80::b9e9:56bc:14aa:d561/128
                                    On-link
  1    306 ff00::/8                 On-link
 14    261 ff00::/8                 On-link
===========================================================================
Persistent Routes:
 If Metric Network Destination      Gateway
  0 4294967295 ::/0                     fe80::ffff:1:1
===========================================================================
192.168.130.0/24 is the VPN connected client network

Thanks for looking into this

--Thomas

solo
Posts: 1387
Joined: Sun Feb 14, 2021 10:31 am

Re: Softether Bridge and Client on same server - L2TP stops working

Post by solo » Tue Jun 18, 2024 8:20 pm

Hi, one more test with "No Adjustments of Routing Table" set, and SE virtual NIC preset to metric=999
?

tstalzer
Posts: 3
Joined: Wed May 12, 2021 6:11 pm

Re: Softether Bridge and Client on same server - L2TP stops working

Post by tstalzer » Thu Jun 20, 2024 9:00 am

Thank you very much - with Metric 999 it is working now perfectly.

Softether is a great tool!!

--Thomas

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