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Softether - Acquiring an IP address from the DHCP server failed

Offline pmulroney

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Hi Everyone,
I'm planning to work remotely from my office, and I tried to turn on the SoftEther VPN service that I've had running.  We've used this in the past quite effectively.  Once we got it setup, it has worked well.

This time however, when I attempt to connect my client, it goes through the process and then immediately terminates the session.

I get something like this in the vpn server_log:

2022-05-16 08:53:19.726 L2TP PPP Session [1.146.152.113:1701]: Acquiring an IP address from the DHCP server failed. To accept a PPP session, you need to have a DHCP server. Make sure that a DHCP server is working normally in the Ethernet segment which the Virtual Hub belongs to. If you do not have a DHCP server, you can use the Virtual DHCP function of the SecureNAT on the Virtual Hub instead.
2022-05-16 08:53:29.648 L2TP PPP Session [1.146.152.113:1701]: The VPN Client sent a packet though an IP address of the VPN Client hasn't been determined.
2022-05-16 08:53:29.648 L2TP PPP Session [1.146.152.113:1701]: A PPP protocol error occurred, or the PPP session has been disconnected.


I tried turning on SecureNAT, but that seemed to create even more problems.  How can I diagnose this issue?

Offline pmulroney

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Re: Softether - Acquiring an IP address from the DHCP server failed
« Reply #1 on: May 16, 2022, 03:52:58 AM »
SOLVED: I restarted the bridge service and all is well!

service bridge restart

Offline Jean-Philippe Pialasse

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Re: Softether - Acquiring an IP address from the DHCP server failed
« Reply #2 on: May 16, 2022, 01:49:38 PM »
it has always been this way. We should find a way to have softether do this. This need to be done also on a regular basis. if you have it working in sme9 yiu might have a cron added to make it work.
other workaround i used was to have softether use its own local network.

Offline pmulroney

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Re: Softether - Acquiring an IP address from the DHCP server failed
« Reply #3 on: May 17, 2022, 03:39:53 PM »
That's a good question!  I don't remember writing a cron to do this, but then again I don't remember what I had for breakfast, so, you know ...

I did try to use the SecureNAT and DHCP functions, but it still seemed to block traffic from the VPN which defeats the purpose!

Offline TerryF

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Re: Softether - Acquiring an IP address from the DHCP server failed
« Reply #4 on: May 18, 2022, 03:40:37 AM »
I had been using softether for years on SME9 needed a cron to restart bridge every 24hrs, when I updated RSLs server to SME10 reinstalled softether and the bridge interface with latest versions, deleted the cron, been fine since..

[root@server ~]# rpm -q smeserver-bridge-interface
smeserver-bridge-interface-0.2-7.el7.sme.noarch

[root@server ~]# rpm -q smeserver-softethervpn-server
smeserver-softethervpn-server-4.34-7.el7.sme.x86_64

[root@server ~]# systemctl status bridge
● bridge.service - Bridge Interface for VPN use.
Loaded: loaded (/usr/lib/systemd/system/bridge.service; enabled; vendor preset: enabled)
Active: active (exited) since Thu 2022-04-14 11:03:02 AEST; 1 months 3 days ago
Main PID: 1395 (code=exited, status=0/SUCCESS)
Memory: 0B
CGroup: /system.slice/bridge.service

Apr 14 11:02:56 server.rsl.org.au systemd[1]: Starting Bridge Interface for VPN use....
Apr 14 11:03:02 server.rsl.org.au bridge-run[1395]: Starting Bridge Service: [ OK ]
Apr 14 11:03:02 server.rsl.org.au systemd[1]: Started Bridge Interface for VPN use..
--
qui scribit bis legit

Offline pmulroney

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Re: Softether - Acquiring an IP address from the DHCP server failed
« Reply #5 on: May 18, 2022, 05:12:46 AM »
Hi Terry,
I've just run the same commands here:

Quote
[root@mail ~]# rpm -q smeserver-bridge-interface
smeserver-bridge-interface-0.2-7.el7.sme.noarch
[root@mail ~]# rpm -q smeserver-softethervpn-server
smeserver-softethervpn-server-4.34-7.el7.sme.x86_64
[root@mail ~]# systemctl status bridge
● bridge.service - Bridge Interface for VPN use.
Loaded: loaded (/usr/lib/systemd/system/bridge.service; enabled; vendor preset: enabled)
Active: active (exited) since Mon 2022-05-16 09:41:42 AWST; 2 days ago
Process: 22449 ExecStop=/sbin/e-smith/systemd/bridge-run stop (code=exited, status=1/FAILURE)
Process: 22861 ExecStart=/sbin/e-smith/systemd/bridge-run start (code=exited, status=0/SUCCESS)
Main PID: 22861 (code=exited, status=0/SUCCESS)
Memory: 0B
CGroup: /system.slice/bridge.service

May 16 09:41:39 mail.logicaldevelopments.com.au systemd[1]: bridge.service failed.
May 16 09:41:39 mail.logicaldevelopments.com.au systemd[1]: Starting Bridge Interface for VPN use....
May 16 09:41:42 mail.logicaldevelopments.com.au bridge-run[22861]: Starting Bridge Service: [ OK ]
May 16 09:41:42 mail.logicaldevelopments.com.au systemd[1]: Started Bridge Interface for VPN use..

It seems to be working OK now. Maybe there was a software update the caused the bridge to not restart or something?

Offline TerryF

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Re: Softether - Acquiring an IP address from the DHCP server failed
« Reply #6 on: May 18, 2022, 08:17:45 AM »
yeah, not sure mate...on yours looking at the time stamp, service only been up a short time..mine has been running for over a month, so fingers crossed its all up from here for you..

there have been some recent updates to do with dchp etc as well, details, when escapes me..
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Offline Jean-Philippe Pialasse

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Re: Softether - Acquiring an IP address from the DHCP server failed
« Reply #7 on: May 18, 2022, 02:12:52 PM »
if you see anything after next update, Terry, then we will know !