Why does Zyxel Keenetic Giga II lose PPPoE?

Question

Computer networks

Hello! I recently exchanged my Zyxel Keenetic Giga 2 under warranty for a new one. Changed due to regular loss of PPPoE connection. As a result, the new router behaves almost the same, only the connection loss intervals have changed. If earlier it held a session for a maximum of a couple of hours, now the new router holds for about 12-18 hours, after which it can’t break and connect for a long time, if you plug the cable into the WAN port, it establishes connections almost immediately.
At this point, the following happens in the logs:

[E] Dec 29 19:45:46 ndm: Service: "PPPoE0" unexpectedly stopped.
[I] Dec 29 19:45:49 pppd[279]: Plugin rp-pppoe.so loaded.
[I] Dec 29 19:45:49 pppd[279]: pppd 2.4.4 started by root, uid 0
[I] Dec 29 19:45:49 pppd[279]: Found unterminated session: 26738:ac:85:3d:92:04:15
[I] Dec 29 19:45:49 pppd[279]: Sent PADT
[I] Dec 29 19:45:50 pppd[279]: PADS: Service-Name: ''
[I] Dec 29 19:45:50 pppd[279]: PPP session is 19379
[I] Dec 29 19:45:50 pppd[279]: using channel 4
[I] Dec 29 19:45:50 pppd[279]: Using interface ppp0
[I] Dec 29 19:45:50 pppd[279]: Connect: ppp0 <--> eth2.3006
[I] Dec 29 19:45:50 pppd[279]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x8e69d636>]
[I] Dec 29 19:45:53 pppd[279]: rcvd [LCP ConfReq id=0x2 <mru 1492> <auth pap> <magic 0x5c8f5bd>]
[I] Dec 29 19:45:53 pppd[279]: sent [LCP ConfAck id=0x2 <mru 1492> <auth pap> <magic 0x5c8f5bd>]
[I] Dec 29 19:45:53 pppd[279]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x8e69d636>]
[I] Dec 29 19:45:56 pppd[279]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x8e69d636>]
[I] Dec 29 19:45:56 pppd[279]: rcvd [LCP ConfReq id=0x3 <mru 1492> <auth pap> <magic 0x5c8f0f6>]
[I] Dec 29 19:45:56 pppd[279]: sent [LCP ConfAck id=0x3 <mru 1492> <auth pap> <magic 0x5c8f0f6>]
[I] Dec 29 19:45:59 pppd[279]: rcvd [LCP ConfReq id=0x4 <mru 1492> <auth pap> <magic 0x5c80075>]
[I] Dec 29 19:45:59 pppd[279]: sent [LCP ConfAck id=0x4 <mru 1492> <auth pap> <magic 0x5c80075>]
[I] Dec 29 19:45:59 pppd[279]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x8e69d636>]
[I] Dec 29 19:46:02 pppd[279]: rcvd [LCP ConfReq id=0x5 <mru 1492> <auth pap> <magic 0x5c8a218>]
[I] Dec 29 19:46:02 pppd[279]: sent [LCP ConfAck id=0x5 <mru 1492> <auth pap> <magic 0x5c8a218>]
[I] Dec 29 19:46:02 pppd[279]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x8e69d636>]
[I] Dec 29 19:46:05 pppd[279]: rcvd [LCP ConfReq id=0x6 <mru 1492> <auth pap> <magic 0x5c8c69d>]
[I] Dec 29 19:46:05 pppd[279]: sent [LCP ConfAck id=0x6 <mru 1492> <auth pap> <magic 0x5c8c69d>]
[I] Dec 29 19:46:05 pppd[279]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x8e69d636>]
[I] Dec 29 19:46:08 pppd[279]: rcvd [LCP ConfReq id=0x7 <mru 1492> <auth pap> <magic 0x5c8e9df>]
[I] Dec 29 19:46:08 pppd[279]: sent [LCP ConfAck id=0x7 <mru 1492> <auth pap> <magic 0x5c8e9df>]
[I] Dec 29 19:46:08 pppd[279]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x8e69d636>]
[I] Dec 29 19:46:11 pppd[279]: rcvd [LCP ConfReq id=0x8 <mru 1492> <auth pap> <magic 0x5c8daa1>]
[I] Dec 29 19:46:11 pppd[279]: sent [LCP ConfAck id=0x8 <mru 1492> <auth pap> <magic 0x5c8daa1>]
[I] Dec 29 19:46:11 pppd[279]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x8e69d636>]
[I] Dec 29 19:46:14 pppd[279]: rcvd [LCP ConfReq id=0x9 <mru 1492> <auth pap> <magic 0x5c89d7c>]
[I] Dec 29 19:46:14 pppd[279]: sent [LCP ConfAck id=0x9 <mru 1492> <auth pap> <magic 0x5c89d7c>]
[I] Dec 29 19:46:14 pppd[279]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x8e69d636>]
[I] Dec 29 19:46:17 pppd[279]: rcvd [LCP ConfReq id=0xa <mru 1492> <auth pap> <magic 0x5c8bb44>]
[I] Dec 29 19:46:17 pppd[279]: sent [LCP ConfAck id=0xa <mru 1492> <auth pap> <magic 0x5c8bb44>]
[I] Dec 29 19:46:17 pppd[279]: sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x8e69d636>]
[W] Dec 29 19:46:20 pppd[279]: LCP: timeout sending Config-Requests 
[I] Dec 29 19:46:20 pppd[279]: Connection terminated.
[I] Dec 29 19:46:20 pppd[279]: Sent PADT
[I] Dec 29 19:46:20 pppd[279]: Modem hangup
[I] Dec 29 19:46:20 pppd[279]: Exit.
[E] Dec 29 19:46:20 ndm: Service: "PPPoE0" unexpectedly stopped.

I tested with two other routers, they keep the session stable, without interruptions.
Of course, the easiest way is to take it back to the store and return it under warranty, but I really like the router, I don’t even know which alternative to choose. Perhaps someone has encountered such a problem or can someone help decipher the logs and tell you in which direction to drip further, what is the reason for this behavior?
UPD: At the moment the problem remains unresolved. ZyXEL support says that the problem is with the provider, since it can be seen in the logs and packet dump that no ACK is coming from the provider. I talked with the support of the provider for a very long time, they did not find any problems in their network.
To weed out problems with the provider, I decided to connect the cable to the computer directly. VLAN'y set using Realtek Diagnostic Utility. The connection is stable for a long time, however, as soon as I insert the cable back into the Keenetic Giga 2, there are constant breaks. Now I handed over the router under warranty, while Keenetic Giga 2 is under examination, I was given out from the Keenetic 4G replacement fund. This router keeps the connection for 28 days. In my opinion, it makes no sense to blame the provider, alternative equipment from the same ZyXEL works stably, but Giga 2 fails.
Confirmation of my words that the connection is active for 28 days on Keenetic 4G:

Answer 1

I'll answer myself. By exchanging two Keenetic Giga II routers under warranty. The third router still earned. I did not notice any breaks on the third router. Most likely those two routers are a marriage. It is not clear why ZyXEL support was blamed by the provider, if the connection was stable with other routers, but not with Keenetic Giga 2. I spent a lot of time and nerves on solving the problem, but in the end everything ended well.
If someone has a similar problem, immediately take the router to the store and write a claim in which you indicate the defect and demand an exchange. If the seller conducts an examination, I recommend that you ask the store to provide a replacement router for this time. It will be possible to test the Internet with another router.

Answer 2

Try contacting Zyxel support, sd.zyxel.ru should help you there.

Answer 3

I have the same router model. Of course, there are breaks, but very rarely, usually when I sinned on the quality of the channel with the provider.
About the Zyxel Keenetic Giga II, I’ll say from myself that the factory firmware on it is less usable than on my past, which was left with the parents of the Zyxel Keenetic II.

Answer 4

As I understand it, in the zuksele all ports are gigabit? Are other routers that work well also gigabit ports? Perhaps from the provider's side the port on the switch is 100Mbps.

Answer 5

I am writing from the future, 2019, Keenetic Viva, the latest firmware - the same problem.
I'm not sure that replacing the device will help and I still want to figure out what the reason is.

Answer 6

I join your discussion and "Keenetic DSL" also loses PPPOE. Already tried everything and all in vain.