TL-ER6020 L2TP Timeout

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TL-ER6020 L2TP Timeout

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TL-ER6020 L2TP Timeout
TL-ER6020 L2TP Timeout
2019-05-06 19:50:36 - last edited 2021-04-19 12:03:22
Model: Adapter  
Hardware Version: V2
Firmware Version: 2.0.2 Build 20180702 Rel.59031

Good afternoon,

    I was curious if anyone else has seen this trouble, or may have a recommendation.

    I have a TL-ER6020 V2 on the latest firmware. I was connecting via PPTP for a few months will no troubles.
For security sakes I moved to L2TP a few weeks ago. I began to notice the VPN drop once a day, every day.
I have other L2TP vpns that I can leave up the entire work day without trouble on the same machine, I'm not convinced it's a PC error. 

For the last 3 work days, my VPN dropped at exactly 7 hours, 36 minutes, and 31 seconds of uptime (per the logs, baring any rounding errors).
Before I contact support to check on firmware bugs, I figured I'd check with the group.

Any thoughts?
Thank you,
Travis

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#1
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9 Reply
Re:TL-ER6020 L2TP Timeout
2019-05-08 10:36:14 - last edited 2021-04-19 12:03:22
If you know the exact timeout, then just try to get dumps at the moment of disconnection, so you will see, who is the initiator of disconnection, PC or router.
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#2
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Re:TL-ER6020 L2TP Timeout
2019-05-08 19:50:31 - last edited 2021-04-19 12:03:22

I was able to get a capture this afternoon.
 

Traffic was flowing fine, then at 7 hours, 36 minutes, and 31 seconds of uptime I received:

TL-ER6020 --> PC [ ISAKMP Informational ]
TL-ER6020 <-- PC [ ISAKMP Informational ]
TL-ER6020 --> PC [ PPP LCP Termination Request ]

I'm not certain if the Router didn't like the informational or what not, but whatever transpires at that point makes the ER6020 request a disconnect.

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#3
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Re:Re:TL-ER6020 L2TP Timeout
2019-05-09 01:53:42 - last edited 2021-04-19 12:03:22

Sprag-O wrote

I was able to get a capture this afternoon.
 

Traffic was flowing fine, then at 7 hours, 36 minutes, and 31 seconds of uptime I received:

TL-ER6020 --> PC [ ISAKMP Informational ]
TL-ER6020 <-- PC [ ISAKMP Informational ]
TL-ER6020 --> PC [ PPP LCP Termination Request ]

I'm not certain if the Router didn't like the informational or what not, but whatever transpires at that point makes the ER6020 request a disconnect.

 

Hi Sprag

 

You can try not to use IPsec to encrypt. I remember that IPsec has the life time, it may cause the VPN re-connect. If you disable IPsec and haven't the problem again, it should be related to the IPsec life time. But it should re-connect automatically.

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#4
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Re:Re:Re:TL-ER6020 L2TP Timeout
2019-05-10 11:41:04 - last edited 2021-04-19 12:03:22

Looks like we can confirm it's IPSEC related. 

L2TP VPN w/o IPSEC encryption stayed up overnight, 21 hours and going.
With IPSEC enabled I can replicate this on multiple PC's.

Where do we go from here? Is there a good place to report bugs?

 

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#5
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Re:Re:Re:Re:TL-ER6020 L2TP Timeout
2019-05-13 09:06:24 - last edited 2021-04-19 12:03:22

Sprag-O wrote

Looks like we can confirm it's IPSEC related. 

L2TP VPN w/o IPSEC encryption stayed up overnight, 21 hours and going.
With IPSEC enabled I can replicate this on multiple PC's.

Where do we go from here? Is there a good place to report bugs?

 

No, it is better to report to technical support of your country directly and bomb them to fix it for you.

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#6
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Re:Re:Re:Re:TL-ER6020 L2TP Timeout
2019-05-15 03:10:31 - last edited 2021-04-19 12:03:22

Sprag-O wrote

Looks like we can confirm it's IPSEC related. 

L2TP VPN w/o IPSEC encryption stayed up overnight, 21 hours and going.
With IPSEC enabled I can replicate this on multiple PC's.

Where do we go from here? Is there a good place to report bugs?

 

 

As I know, IPsec must set up the life time. When the life time is over, the VPN will re-negotiate, but generally it will not take a long time for re-negotiate. If your application doesn't need to keep online all the time, it's not a problem.

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#7
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Re:Re:Re:Re:Re:TL-ER6020 L2TP Timeout
2019-06-21 01:17:53 - last edited 2021-04-19 12:03:22

I've been back and forth with support for the last few weeks.
I'm on the second round of beta sw (2.0.2 Build 20190422 Rel.56747) and factory resets.

It's unclear what the underlying issue may have been, support said this newest beta 'Solves a lot of problems'.

It looks like before if a negogiation failed, the router wouldn't retry and requested a disconnect. It may have been failing before at 7h36m and not reporting in the logs. Now occasionally when a negotiation is missed (more are appearing than before) it retries and succeeds. Not certain if this is a work around for an actual negotiation issue, but it seems to work.

The L2TP tunnel has been up for 14 hours at this point, appearing like it may be fixed.

Just wanted to put this out there in case anyone else runs across a VPN issue.

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#8
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Re:Re:Re:Re:Re:Re:TL-ER6020 L2TP Timeout
2019-06-24 08:11:48 - last edited 2021-04-19 12:03:22

Could you upload that beta fw here?

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#9
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Re:Re:Re:Re:Re:Re:Re:TL-ER6020 L2TP Timeout
2019-07-31 19:28:07 - last edited 2021-04-19 12:03:22
I'm not certain I'm allowed to share the beta fw, it is labeled confidential. I will note, it looks like it's a band-aid. I believe at the interval there was a key exchange that always failed. Now It appears to be retrying before dropping the tunnel. This results in a blip, one long enough to kill my noticeable udp streams. A few seconds later everything comes back and works as intended.
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#10
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